It’s no secret that Neuroendocrine Cancer can be difficult to diagnose. Although earlier diagnosis is improving (as reported in the SEER database report issued in 2017), there is still a lot of ground to cover. It’s also no secret that certain cancers are difficult to diagnose (NETs is one) and there are a number of reasons why this happens, including but not limited to: – they grow silently, they often produce vague symptoms which can be mistaken for much more common illnesses, and their complexity is not fully understood.
I wanted to cover two different aspects of the problem of finding NETs. Firstly, in finding the primary tumour so that the type of NET can be properly established – this drives the best treatment regime. Secondly in finding all the tumours, as this establishes the correct and most detailed staging declaration – this drives treatment plans and surveillance regimes that need to be put into place.
Hunting Tumours – Primary vs Secondary
It’s really important to determine which tumours are primary and which are secondary (metastasis). There’s a number of ways to help work this out and knowledge of NETs epidemiology studies can help.
Specialist Knowledge – certain things are known about the behaviour of NETs
Specialists and in particular NET specialists will be aware of the vagaries of NETs in terms of what tumours are normally a primary and which are normally secondary and many of the pitfalls involved in working that out. Many NETs will have metastasized to the liver at diagnosis, so whilst it is not impossible to have a primary liver NET, the vast majority of liver tumours found will be secondary (metastases). NET Specialists are more likely to have the experience than generalists. They know that the varying metastatic potential depending on the primary site clearly indicates differing biology and genetics across sites and they know that NETs are indeed a heterogeneous group of tumours. The differences cannot be explained by whether the NET is situated in the foregut, midgut, or hindgut. For example, Appendiceal NET is known to be less prone to metastasis. This may be due to the high rate of incidental ﬁndings during appendectomies, or because the appendix is an immunological organ where malignant cells can therefore be expected to be frequently recognized by the immune system.
The majority of the digestive tract is drained by the portal venous system, explaining the dominance of liver metastases in this group of tumours. This also explains our ﬁnding that many nervous system and bone metastases originate from NETs in the lungs. Disseminated tumour cells may directly reach the systemic circulation from the lungs, whereas if originating from the midgut region, they need to ﬁrst pass both the liver and the lungs.
As an example of this heuristic knowledge, one Swedish study indicated that two-thirds of peritoneal metastases will be attributed to Small Intestine NETs (SI NETs). SI NETs and Pancreatic NETs (pNETs) are the most likely to metastasize. The least likely sites to metastasize are the Appendix and Rectum. The same study indicated that in addition to the common metastatic locations of lymph nodes and liver, Lung NETs are more likely to metastasize to the brain and bone than other types. I believe the findings from this study more or less correlates to other information I’ve had access to and also confirms the technical behaviour paragraph above.
There are many other clues open to those involved in diagnosing a NET:
Patient. Very often the patient plays a big part of determining where the primary and other tumours might be by carefully describing symptoms.
Incidental Finds. NETs are very often found incidentally during trips to the ER/A&E and also during tests for something else. This is particularly the case with Appendiceal NETs and might explain why the average age of a patient is significantly lower in this type of NET.
Blood tests and Hormone Markers. We are not yet in a position where these types of tests can diagnose (but we are moving in that direction). In the case of unknown primaries (CUP), sometimes test results can help to find where some of these cancers started. With NETs, symptomatic patients can often test to confirm an elevated hormone marker which may narrow it down to a specific organ or gland. Read more here.
Scans and Endoscopies. Most cancers of a certain size may show up on conventional scanning such as CT, MRI and Ultrasound. Nuclear scans are now playing a bigger part in finding tumours which betray their location through functional behaviour by lighting up or glowing on these imaging devices. Endoscopies (e.g. gastroscopies, colonoscopies, even gastro intestinal pill cameras can be used) can help but like scans are not foolproof). Generally with NETs, if you can see it, you can detect it. Read more here.
Hereditary Conditions. Around 5-10% of NETs are hereditary in nature, mostly involving the MEN group of syndromes. Many of those people will know they are at risk of developing NETs and their doctors should know the most common locations for primary tumours associated with each gene. So a declared or suspected hereditary syndrome is useful in finding primary tumours if they exist and are proving difficult to find.
Biopsies. “Tissue is the issue”. Pathology can very often give really strong clues as to the type of NET and therefore the likely location of a primary tumour, for example additional tests such as immunostains. Many biopsies will come from secondary cancer (metastases), mostly the liver. Despite all the potential diagnostic routes above, the place the cancer started is sometimes still not found and this may lead to atypical diagnostic/treatment plans and in certain cases this might even include exploratory biopsies via surgery (invasive/minimally invasive), perhaps combined with opportunistic tumour removal if found during the procedure.
Staging. Simple staging can be given if locations of metastases are known. For example in the case of Liver metastases, the stage is automatically Stage 4. However, the full staging definition relies on knowing distant metastases, loco-regional metastases and the full Tumour/Node/Metastases (TNM) definition (size, spread, etc) cannot be given without a primary. Read more here.
Cancers of Unknown Primary
Cancer is always named for the place where it started, called the primary site. Sometimes doctors can’t tell where a cancer may have started. When cancer is found in one or more places where it seems to have spread, but the site where it started is not known, it is called a cancer of unknown primary (CUP) or an occult primary cancer.
When you look at the ratio of all cancers, the figure for cancers of unknown primary (CUP) is quite startling. Depending on where you look the figure is around 2-10%. That doesn’t seem a lot but when you consider the amount of people diagnosed with cancer, the total figure must be staggering. Interestingly, Cancer Research UK say that 60% of CUP cases are in the over 75s. In another interesting Swedish study, doctors claimed that the rates of metastatic cases were higher with certain NETs than they were in their anatomical counterparts, reinforcing the dangerous and sneaky nature of NETs.
Despite quite advanced scanning and diagnostic testing currently in place, and the extensive knowledge of NET specialists, there can still be reasons for not being able to find the primary tumour:
The primary is just too small to be seen and is growing quite slow. Very small cancers might not cause symptoms or be seen on scans. This is a particularly relevant point with NETs.
The primary could be hidden in tissue in between different organs causing confusion about the actual primary location.
The body’s immune system killed the primary cancer. It’s also possible (but not common) that any secondary cancer (i.e. metastases) is still growing.
The tumour has become loose from its primary location and exited the body, e.g. from a wall of the bowel and excreted out in the stool.
The primary cancer was removed during surgery for another condition and doctors didn’t know cancer had formed. For example, a uterus with cancer may be removed during a hysterectomy to treat a serious infection.
I hope this is useful for many NET patients, particularly those who are looking for a diagnosis or looking for a primary tumour.
Neuroendocrine Cancer – at times, it can really be like looking for a needle in a haystack.
This is a ‘next generation’ Peptide receptor radionuclide therapy (PRRT) or more specifically the radiopharmaceutical that binds to both activated and unactivated somatostatin receptors which are upregulated on these tumours. There is far higher binding via this mechanism than standard octreotate. The technical name of the radiopharmaceutical is Satoreotide tetraxetan lutetium-177 (author’s note, I’m guessing but it could be a variant of Lanreotide). It was once named JR11.
What’s the difference to the current approved therapy?
Conventional PRRT (e.g. Lutathera, Lu177 Dotatate) is based on a somatostatin receptor ‘agonist’ approach, whereas 177Lu Ops 201 Satoreotide is a receptor ‘Antagonist’. The differences are quite technical but in the most layman terms , the antagonist has the capability of attaching (binding) to more receptors, including those in a ‘resting’ or ‘inactive’ state, spends more time on the tumor than agonist based therapies. The result is a higher number of receptor binding sites and greater tumor uptake. In addition it is said to show an improved tumor-to-kidney dose ratio compared to 177Lu-DOTA-TATE.
This would also be reflected in the theranostic use of the drug in Ga68 imaging (i.e. Ga68 Satoreotide).
The clinical trial is named “Study to Evaluate the Safety and Preliminary Efficacy of 177Lu-OPSC001 in NETs”. The protocol involves 3 cycles 8 weeks apart of intravenous Lu-177 OPS-201. All patients will have baseline Ga-68 octreotate imaging performed.
The treatment is available for all NET patients with a histologically confirmed diagnosis of:
unresectable GEP NET (Grade I and Grade II according to WHO classification (2010, Annex 01), functioning and non-functioning).
unresectable “typical lung NET” or “atypical lung NET” are acceptable (with the exception of Large Cell Bronchial Neuroendocrine Neoplasms and Small Cell Lung Cancers).
malignant, unresectable pheochromocytoma or paraganglioma
Patients who have previously had Lu-177 octreotate (e.g. Lutathera) are not eligible. Patients may have had any other treatment including chemotherapy, radiotherapy or Somatostatin Analogues (e.g. octreotide, landreotide).
There are other inclusion and exclusion criteria to be found within the clinical trial document. The trial is due to compete in May 2022.
Where is the Trial based?
At the time of writing and according to the Clinical Trial document, Australia (Melbourne and Perth), Austria (Vienna), Denmark (Aarhus), Switzerland (Basel), UK (Royal Free London). Two sites are also listed in France (Nantes and Toulouse) but trial document currently marked as not yet recruiting.
I have anecdotal evidence to suggest one more UK site is possible in 2019, Windsor in UK, a private healthcare provider but it will be open to public and private patients.
What about USA?
I also found an additional trial based in Memorial Sloan Kettering New York designed to take a theranostic approach by using Satoreotide (JR11) for the pre-treatment imaging, e.g. Ga68 satoreotide (JR11) and the 177Lu version for treatment. The clinical trial document indicates this trial is active but NOT RECRUITING and is entitled “Theranostics of Radiolabeled Somatostatin Antagonists 68Ga-DOTA-JR11 and 177Lu-DOTA-JR11 in Patients With Neuroendocrine Tumors”
Thanks for reading
You may also find these PRRT related articles useful:
Neuroendocrine Cancer is one of a number of “difficult to diagnose” conditions. Many types of Neuroendocrine Cancer come with an associated syndrome and these syndromes can mimic everyday illnesses. In some cases, many people don’t feel ill while the tumours grow. Most types of this cancer are slow-growing but there are also aggressive versions. Although things appear to be improving in diagnostic terms, it can sometimes take years for someone to be finally diagnosed correctly and get treatment, albeit in some cases, too late for any hope of a curative scenario. It’s a very sneaky type of cancer and if left too long it can be life threatening – CLICK HERE to find out why.
The road to a diagnosis of Neuroendocrine Cancer is often not straight or easy to navigate. It’s not only a sneaky type of cancer but it’s also very complex. It’s a heterogeneous group of malignancies with a varied and confusing histology and nomenclature to match. As I said above, many people are asymptomatic for years whilst the tumor grows and some might say that it’s somewhat ‘lucky’ to have symptoms to help aid a diagnosis. Many find that a lack of knowledge of Neuroendocrine Cancer in primary care, doesn’t always produce results. Common misdiagnoses include (but not limited to), Irritable Bowel Syndrome (IBS) and other common digestive diseases, menopause, appendicitis, hypertension, gastritis, asthma. Neuroendocrine Cancer is much more likely to be diagnosed at secondary care if a referral for ‘something’ can be achieved.
……..cue internet searches (Dr Google)
I think the rise and the power of the internet and rise of social media applications is very much helping generate awareness and knowledge of Neuroendocrine Cancer and those looking for a diagnosis may find help in this way. I suspect this instant access to information has played its part in the diagnostic improvements I mentioned above. Take my own efforts for example, I’m a wee Scottish guy with a computer and I’m already accelerating towards a million blog views – there’s clearly a market for what I produce. In terms of those looking for a diagnosis, if only one gets an earlier diagnosis due to my site, I’ll be happy.
Unfortunately, the internet can often be a minefield and in many cases, can lead to quite unnecessary worry for those looking for a solution.
I’m contacted almost daily by the ‘undiagnosed’ who suspect they have Neuroendocrine Cancer, often because they appear to be displaying the symptoms of one of the associated syndromes. These are some of my most difficult questions. I’m always very wary of initially agreeing with their assumptions and logic, instead opting for straightforward detective work based on my knowledge of the different types of Neuroendocrine Cancer, knowledge of the best scans, tumour markers, hormone markers. And I always warn them that statistically, they are more likely to have a common condition than the less common Neuroendocrine Cancer.
Many have already had multiple doctor’s appointments and tests. If they have not yet had a scan, I encourage them to try to get one ‘by hook or by crook’. Despite what you read on patient forums and surveys, the vast majority of Neuroendocrine diagnoses will be triggered by a conventional imaging such as CT and/or MRI. If you can see it, you can detect it.
When I first chat with the ‘undiagnosed’, I find many of them are fairly knowledgeable about Neuroendocrine Cancer and other health conditions, again confirming the power of the internet and the savvy ‘internet patient’. This is fine if you look in the right places of course – for certain things there are more wrong places on the internet than right ones.
If I have time, I’m happy to chat with these people, some are very frustrated – in fact some are so frustrated that they just want a diagnosis of something even if that something is really bad. Some are not showing anything on any scan but in certain cases, it can be likened to finding a needle in a haystack.
What do you say to someone who is utterly convinced they have Neuroendocrine Cancer but CT/MRI/Octreoscan/Ga68 PET are all clear, Chromogranin A and 5HIAA are in range but they still say they have (say) diarrhea with its potential for literally thousands of differential diagnoses. It’s a tough gig.
My scan came back normal. That should be good news. But, if there is no tumor, how can I be suffering from all the symptoms of carcinoid syndrome? Is that diagnosis wrong? Are the urine and blood test results wrong? I’m awaiting a MRI scan to take another look to see if the doctor can find anything. I don’t know what they’ll find. I don’t want them to find anything. But I’m afraid of what will happen if they don’t.
I always let the undiagnosed know that Neuroendocrine Cancer patients are some of the most friendliest and helpful people you can meet, they will treat you as one of their own. There will be a number of diagnosed people online who have gone through what the undiagnosed are going through, so they will both sympathise and emphasise. But … this can often have the adverse effect of pushing them into believing they must have Neuroendocrine Cancer. This makes for interesting discussions given the number of people who automatically assume that ‘flushing’ or ‘diarrhea’ (as described by the undiagnosed) must be Neuroendocrine Cancer without any reference to the many differential diagnoses and the context of what that actually means in Neuroendocrine Cancer terms.
10 Questions to ask your doctor/specialist for those Diagnosed with Neuroendocrine Cancer (and where to find a specialist)
I once wrote an article for DIAGNOSED NET Patients suggesting 10 Questions to ask their doctor. So I wanted to take a step back in context, using the knowledge I now have, and put myself in the shoes of someone who thinks they may have Neuroendocrine Cancer but is not yet diagnosed.
Key questions to ask your doctor/specialist for those trying to confirm or discount Neuroendocrine Cancer
Dear undiagnosed people. I totally understand your fear. There’s nothing worse than being ill and not knowing what illness you have. I’ve therefore compiled a list of 3 key questions for you to ask – think of it as a tick list of things to ask your doctor to do or check . I have linked several background articles for you to prepare your case. However, I cannot promise your doctor will agree or take any action, in fact some might be annoyed about the lack of trust. However, doing your homework really helps, including diaries and other evidence.
I also wouldn’t say that a negative to all the questions will mean you definitely do not have Neuroendocrine Cancer but at least these questions might provide your doctor and yourself with some food for thought, perhaps leading to the diagnosis of ‘something’. The questions below assume that routine blood tests have been done, including Full Blood Count, Liver, Renal, Bone, Glucose.
Questions for the UNDIAGNOSED to ask their treating physician
“I think I might have a type of cancer known as Neuroendocrine Cancer or Neuroendocrine Tumours (NET) because <<< insert your own story>>>. Would you please consider the following tests and checks:”
1. Chromogranin A (CgA) is a marker which is quite sensitive for Neuroendocrine Tumours, essentially measuring tumour bulk potentially indicating the presence of Neuroendocrine Tumours. There can be other reasons for an elevated CgA figure, including the patient’s use of proton pump inhibitors (PPI) (see the article for an alterative test where this is the case). Read more here – Neuroendocrine Cancer – Tumour and Hormone Marker tests.
3. Scans. Most NETs can be seen on a CT scan although liver metastasis can often show more clearly on an MRI. There are also nuclear scan options to confirm conventional imaging findings. Some NETs may be accessible via endoscopy and ultrasounds can also give hints for further investigation. In some cases, nuclear scans will find things that conventional imaging cannot because radionuclides can normally pick up oversecreting tumours. Read more in my article “If you can see it, you can detect it”.
You can hear two NET specialists talking about the issues surrounding the diagnostics here.
Edit 10 Jan 2019: RadioMedix and Curium Announce FDA Fast Track Designation For 64Cu-Dotatate. Read more byclicking here.
Curium and RadioMedix Inc. announce an exclusive agreement to develop and commercialize 64Cu-Dotatate, an investigational positron emission tomography (PET) diagnostic agent for patients with Neuroendocrine Tumors (NETs). RadioMedix is currently engaged in Phase III clinical trials of the agent and expects to file a New Drug Application with the Food and Drug Administration in 2019. This partnership builds on the initial development work conducted by RadioMedix and will benefit from Curium’s regulatory, manufacturing, distribution, and commercial expertise. The radionuclide is not new, it’s been in use for some time, mainly in Denmark.
64Cu is a PET isotope that can be produced at a central location in quantities to meet the commercial needs of hospitals and imaging centers without the supply limitations of nuclear generator-based PET isotopes,” said Ebrahim Delpassand, MD, CEO of RadioMedix. “Once approved, 64Cu-Dotatate will be available to patients in medical centers with PET capability across the country. This will address the shortage or lack of availability of somatostatin analogue PET agents that we are currently experiencing in many parts of the U.S.”
Ga68 PET Shortages explained
This statement is in relation to the current shortage of Ga68 PET radionuclide. For those not aware, the Society of Nuclear Medicine and Molecular Imaging (SNMMI) has written a letter to the FDA about ongoing shortages of generators that produce gallium-68 (Ga-68), a radioisotope used regularly in medical imaging. The letter—available here.
The letter explains that Ga-68 is currently used to produce NETSPOT from Advanced Accelerator Applications (a Novartis company), which was approved in June 2016 to help treat neuroendocrine tumors (NETs) in adult and pediatric patients using PET. NETSPOT, however, is only approved using specific generators. And those generators are only approved for either 400 uses or one year, whichever comes first. This has led to shortages throughout the United States.
SNMMI notes some possible remedies for this shortage. For instance, “a temporary exemption to the 400-elution limit would have a major impact on NETSPOT capacity for patients,” according to the letter. In addition, using a wider variety of generators to produce NETSPOT or using cyclotron-produced gallium chloride are two other methods that could improve production in a relatively short amount of time. “Further discussion with the manufacturers is necessary,” the authors added.
Read more about Ga68 PET and its use in Neuroendocrine Cancer – click here. Worth also noting that RadioMedix is also involved in a number of NET related initiatives including:
1. Trials for a new type of PRRT called ‘Targeted Alpha-emitter Therapy (TAT) – I’ve written about this previously. Read my article here.
2. An exclusive distributor for the TM Isotopen Technologien München AG (ITM) PRRT product currently in trial. I wrote about this here.
How does 64Cu-Dotatate compare with Ga68 PET and Octreotide Scans?
To learn more about previous studies on 64Cu-Dotatate, here’s 2 articles published in the Journal of Nuclear Medicine which are a head to head comparison of 64Cu-Dotatate with Ga68 Dotatoc and with 111 Indium Octreotide (Octreoscan).
Conclusion: 64Cu-DOTATATE has advantages over 68Ga-DOTATOC in the detection of lesions in NET patients. Although patient-based sensitivity was the same for 64Cu-DOTATATE and 68Ga-DOTATOC in this cohort, significantly more lesions were detected by 64Cu-DOTATATE. Furthermore, the shelf life of more than 24 h and the scanning window of at least 3 h make 64Cu-DOTATATE favorable and easy to use in the clinical setting.
Conclusion: With these results, we demonstrate that 64Cu-DOTATATE is far superior to 111In-DTPA-OC in diagnostic performance in NET patients. Therefore, we do not hesitate to recommend implementation of 64Cu-DOTATATE as a replacement for 111In-DTPA-OC.
The shortage of Ga68 PET radionuclide caused by limitations of the generators in use is unfortunate. Reading the SNMMI letter, I think progress can be made downstream. However, the introduction of a new scanning agent could be useful as long as the trials prove its safety and efficiently and is comparable to current tools. There is no news of any plans to extend this potential new radionuclide outside the US but I suspect that would change following an FDA approval.
When I was offered my very first Ga68 PET/CT at a 6 monthly surveillance meeting in May 2018, I was both excited and apprehensive. Let me explain below why I had a mix of emotions.
I was diagnosed in 2010 with metastatic NETs clearly showing on CT scan, the staging was confirmed via an Octreotide Scan which in addition pointed out two further deposits above the diaphragm (one of which has since been dealt with). In addition to routine surveillance via CT scan, I had two further Octreotide Scans in 2011 and 2013 following 3 surgeries, these confirmed the surveillance CT findings of remnant disease. The third scan in 2013 highlighted an additional lesion in my thyroid (still under a watch and wait regime, biopsy inconclusive but read on….).
To date, my 6 monthly CT scans seem to have been adequate surveillancecover and all my tumour and hormone markers remain normal. I’m reasonably fit and well for a 62-year-old.
Then I ventured into the unknown
I wrote a comprehensive post about the Ga68 PET entitled “…. Into the unknown” – so named because that is how I felt at the time. It’s well-known that the Ga68 is a far superior nuclear scan to the elderly Octreotide type, showing much greater detail with the advantage of providing better predictions of PRRT success if required downstream. It has been a game changer for many and if you look below and inside my article, you will see statistics indicating just how it can ‘change the game’ in somatostatin receptor positive Neuroendocrine Cancer diagnostics and treatment.
The excitement of the Ga68 PET
I was going to get the latest ‘tech’ and thought it could be useful confirmation of what I already knew. I also felt lucky to get one, they are limited in UK and there has to be a clinical need to get access. I was excited because it might just rubber stamp the stability I’ve enjoyed for the past 5 or so years since my last surgery in 2012.
The apprehension of the Ga68 PET
I also felt apprehensive because of the ‘unknown’ factor with cancer, i.e. what is there lurking in my body that no-one knows about, and which might never harm me but this scan will light it up demanding attention. I was also apprehensive in case this more detailed scan found something potentially dangerous. As we know, NETs are mostly slow-growing but always sneaky. Of course, any new tumours found may not actually be new, they were just not seen until the Ga68 PET was able to uncover them. How annoying!
Is the Ga68 PET Scan a game changer?
To confirm the advantages of SSTR PET over Octreotide scans, a study comprising 1,561 patients reported a change in tumour management occurred in over a third of patients after SSTR PET/CT even when performed after an Octreotide scan.
Overall, change in management occurred in 44% (range, 16%-71%) of NET patients after SSTR PET/CT.
In 4 of 14 studies, SSTR PET/CT was performed after an 111In-Octreotide scan. In this subgroup, additional information by SSTR PET/CT led to a change in management in 39% (range, 16%-71%) of patients.
Seven of 14 studies differentiated between inter- and intramodality changes, with most changes being intermodality (77%); intramodality, (23%). (note: intermodality means changes within the same treatment, intramodality means change to another treatment).
In an older study, this slide from a NET Research Foundation conference shows some more interesting statistics:
Was Ga68 PET a game changer for me?
Yes, I believe so. I’m now in the ‘bone met club’ and although that single metastasis has probably been there for some time, it’s not a ‘label‘ I was keen to add to my portfolio. If I was to be 100% honest, I’m not totally convinced it’s a metastasis. The scan has brought more light onto my thyroid issue. In fact it indicates even more potential issues above the diaphragm including what looks like a new sighting around my left pectoral lymph nodes. The scan also lghts up a known issue in the left clavicle lymph nodes, first pointed out via Octreotide scan in 2010 and biopsy negative.
In addition to a nuclear scan update (routine surveillance), it also formed part of an investigation into progression of my retroperitoneal fibrosis (initially diagnosed 2010 but potential growth spotted on recent surveillance CT). The Ga68 PET doesn’t make fibrosis light up (it’s not cancerous) but there are some hotspots in the area of the aorta close to the fibrosis, a potential source if the cause. Surgery is on hold for now as my kidney function is fine following a renal MAG3 scan which reported no blockages.
It would appear I’m no longer a boring stable patient
The Ga68 PET Scan confirmed:
Bone Metastases. Report indicates “intense focal uptake“. It always amazes me that people can be thankful for having an extra tumour. I’m thankful I only have a single bone metastasis (right rib number 11). I had read so many stories of those who got their first Ga68 PET and came back with multiple bone metastases. I’ll accept one and add to my NET CV. I have no symptoms of this bone metastasis and it will now be monitored going forward. I’m annoyed that I don’t know how long it’s been there though!
Confirmation and better understanding of the following:
Thyroid lesion There is some uptake showing. A 2014 Biopsy of this lesion was inconclusive and actual 2018 Ga68 PET report infers physiological uptake. I’m already diagnosed hypothyroidism, possibly connected. (Edit – on ultrasound in Jan 2019, looks slightly smaller than previous check).
Left Supraclavicular Fossa (SCF) Nodes lighting up “intense uptake“. I’ve had an exploratory biopsy of the SCF nodes, 5 nodes removed negative. Nothing is ‘pathologically enlarged’ in this area. Monitored every 6 months on CT, annually on ultrasound. I had 9 nodes removed from the left axillary in 2012, 5 tested positive for NETs and this area did not light up. This whole area on the left above the diaphragm continues to be controversial. My surgeon once said I had an unusual disposition of tumours. (Edit: Nothing sinister or worryingly enlarged showing on Jan 2019 ultrasound – measuring 6mm).
Report also highlights left subpectoral lymph nodes which is new. The subpectoral area is very interesting as from my quick research, they are closer to the left axillary (armpit) nodes than they are to the SCF nodes. I’m hoping to get an ultrasound of these in January at my annual thyroid clinic (Edit: nothing sinister showing on ultrasound in Jan 2019).
My known liver metastases lit up (remnant from liver surgery 2011) – not marked as intense though. The figure of 3 seems to figure highly throughout my surveillance scans although the PET report said “multiple” and predominately right-sided which fits.
Retroperitoneal area. This has been a problem area for me since diagnosis and some lymph nodes are identified (intense word not used). This area has been highlighted on my 3 octreotide scans to date and was first highlighted in my diagnosis trigger scan due to fibrosis (desmoplasia) which was surrounding the aorta and inferior venous cava, some pretty important blood vessels. I wrote an article on the issue very recently – you can read by clicking here. So this scan confirms there are potentially active lymph nodes in this area, perhaps contributing to further growth of the fibrosis threatening important vessels – read below.
I have learned so much about desmoplasia since this issue arose that I now fully understand why I had to have radical surgery back in 2010 to try to remove as much of the fibrosis as possible from the aortic area. You can read more about this in my article. Desmoplasia via fibrosis is still very much of an unknown and mystery condition in NETs.
I now know that my fibrosis is classed as clinically significant and according to the Uppsala study of over 800 patients inside my article, I’m in 5% of those affected in this way (2% if you calculate it using just the retroperitoneal area).
It appears this problem has come back with new fibrosis or growth of existing fibrosis threatening to impinge on blood vessels related to the kidneys and also my ureters (kidney to bladder urine flow). The Ga68 PET doesn’t make fibrosis light up (it’s not cancerous) but there are some hotspots in the area of the aorta close to the fibrosis.
I didn’t expect this particular problem to return – it was a bit of a shock. My hormone markers have been normal since 2011 and this just emphasises the importance of scans in surveillance.
Conventional Imaging is still important though
There’s still quite a lot of hype surrounding the Ga68 PET scan and I get this. However, it does not replace conventional imaging (CI) such as CT and MRI scans which still have their place in routine surveillance and also in diagnostics where they are normally at least the trigger for ‘something is wrong’. For the vast majority, a CT/MRI scan will find tumours and be able to measure reductions and progress in regular surveillance regimes. In fact, the retroperitoneal fibrosishas appeared on every CT scan since diagnosis but the changes were highlighted on my most recent standalone CT and it triggered the Ga68 PET (although my new Oncologist did say I was due a revised nuclear scan). It’s not a ‘functional’ issue (although it is caused by functional tumours). In fact the fibrosis is not mentioned on the Ga68 PET because it is not lighting up – but the lymph nodes surrounding it are mentioned and they are under suspicious as being active.
Appropriate Use Criteria for Somatostatin Receptor PET Imaging in Neuroendocrine Tumors
There are actually recommended usages for the Ga68 PET scan here. For example, it is not recommended for routine surveillance in place of CI.
Scans – ‘horses for courses’
Read a summary of all conventional scans and nuclear scans by clicking here.
I had a meeting with my Oncologist and Surgeon and a surgical plan is possible in the event of a problem. My surgeon explained it all in his wonderfully articulate and brilliant surgical mind. Fortunately it’s not really urgent but pre-emptive treatment may be required at some point as the consequences of kidney/bladder function are quite severe. Following some further checks, the anticipated surgery is on hold for now as my kidney function is fine following a renal MAG3 scan which reported no blockages. I continue to have monthly renal blood tests and it was hinted another renal MAG3 could be done at the end of the year.
My game has changed, that’s for sure. I’m now entering a new phase and I’m waiting on details of my revised surveillance regime. However, at least my medical team and I now know what WE are dealing with and the risks vs benefits are currently being assessed. I’m heavily involved in that.
Since PRRT was formally approved last year in USA and Europe (and other places), it’s triggered a whole mini-industry in PRRT variants or enhancements. An interesting study from China, a country starting to become very active in the NET world. I guess they have been active for some time given that I’ve seen their NET experts presenting at the last 2 years of ENETS in Barcelona. In this particular study, there is linkages to the Laboratory of Molecular Imaging and Nanomedicine, NIBIB/NIH, Bethesda, Maryland in USA.
This is news of a first-in-human study presented at the 2018 Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging (SNMMI) which demonstrated the benefits and safety of a new, long-lasting type of radionuclide therapy (PRRT) for patients with advanced, metastatic neuroendocrine tumors (NETs) – 177Lu-DOTA-EB-TATE.
How is this different from the current PRRT standard – Lutathera?
“Lu-DOTA-EB-TATE is a “three-in-one” therapeutic compound, with an octreotate peptide to find the tumor, an ‘Evans blue motif’, which uses endogenous albumin as a reversible carrier to effectively extend the half-life in the blood and substantially increase targeted accumulation and retention within the tumor, and a therapeutic radionuclide to kill the tumor cells, to finally provide effective treatment of NETs,” …….. explains Shawn(Xiaoyuan) Chen, PhD, senior investigator, of National Institute of Biomedical Imaging and Bioengineering at the National Institutes of Health , Bethesda, Maryland.
Lutathera-177 (177Lu)-DOTATATE (trade name Lutathera), a peptide receptor radionuclide tharapy (PRRT) with radiolabeled somatostatin analogues (peptides), was recently approved by the USA FDA and the EMA for the treatment of somatostatin receptor positive NETs. It is the therapeutic part of a nuclear medicine theranostic pairing. Gallium-68 (68Ga)-DOTATATE is the diagnostic agent used in PET/CT scans that first locates and marks the lesions for follow-up with targeted PRRT delivery directly to the tumor cells which express high levels of somatostatin receptors (SSTRs). Because the PRRT binds to receptors expressed by the tumor cells, healthy cells are unharmed. However, the peptide quickly clears from the blood through the kidneys limiting the accumulation of radioactivity within tumors and making additional treatment cycles necessary to provide the therapeutic dose.
177Lu-DOTA-EB-TATE. This first-in-human, first-in-class, Phase I trial (ID: NCT03308682) investigated the safety and dosimetry of a novel long-lasting radiolabeled somatostatin analogue that adds an albumin-binding Evans blue (EB, an azo dye) derivative to 177Lu-DOTATATE. Albumin, the most abundant plasma protein in human blood, is a natural transport protein and has a long circulatory half-life. This is an open-label, non-controlled, non-randomized study.
For the study, conducted in collaboration with researchers at the U.S. National Institute of Biomedical Imaging and Bioengineering, 8 patients (6 men and 2 women ranging in age from 27 to 61 years old) with advanced metastatic neuroendocrine tumors were recruited from Peking Union Medical College Hospital and the Chinese Academy of Medical Sciences in Beijing, China.
Each patient underwent whole-body 68Ga-DOTATATE PET/CT. Five of the patients then accepted intravenous injection with a single dose of 0.35-0.70 GBq of 177Lu-DOTA-EB-TATE within one week, and were monitored at 2, 24, 72, 120 and 168 hours after 177Lu-DOTA-EB-TATE administration with serial whole-body planar and single photon emission computed tomography (SPECT)/CT images acquired. The other 3 patients accepted a dose of 0.28-0.41 GBq of 177Lu-DOTATATE and were monitored at 1, 3, 4, 24 and 72 hours with the same imaging procedures. Complete physical examinations, including vital signs, blood count, biochemistry, and immunology analyses were performed immediately before and 1, 3, and 7 days, as well as 3 months, after treatment.
Administration of 177Lu-DOTA-EB-TATE was well tolerated, with no adverse symptoms reported throughout the procedure and follow-up. The total effective dose equivalent and effective dose were 0.2048 ± 0.1605 and 0.0804 ± 0.0500 mSv/MBq for 177Lu-DOTA-EB-TATE and 0.1735 ± 0.0722 and 0.0693 ± 0.0317 mSv/MBq for 177Lu-DOTATATE. The liver, kidneys, bone marrow and total body received slightly higher doses (mGy/MBq) with 177Lu-DOTA-EB-TATE than with 177Lu-DOTATATE, while the spleen received lower doses with 177Lu-DOTA-EB-TATE. Blood clearance of 177Lu-DOTA-EB-TATE was also slower. Most importantly, 177Lu-DOTA-EB-TATE lasted in the tumors more than 4 times longer than 177Lu-DOTATATE.
Jingjing Zhang and Zhaohui Zhu of Peking Union Medical College Hospital point out, “By introducing an albumin binding moiety, this long-lasting radiolabeled somatostatin analogue has remarkably enhanced uptake and retention in SSTR-positive tumors, which is important to increase the therapeutic efficacy in patients. With proper selection of patients with advanced metastatic neuroendocrine tumors, 177Lu-DOTA-EB-TATE has great potential to be a highly effective treatment, while providing a safe dose with less frequency of administration than is possible with 177Lu-DOTATATE.”
Scans were done at 2, 24, 72, 120 and 168 hours after the administration of 177Lu-DOTA-EB-TATE. The radiopharmaceutical cleared from the blood pool over time and persistently retained in the tumors (arrows). Credit: J Zhang et al., Peking Union Medical College Hospital, Beijing, China; X Chen et al., Laboratory of Molecular Imaging and Nanomedicine, NIBIB/NIH, Bethesda, MD
Abstract 118: “Safety, Pharmacokinetics and Dosimetry of a Long-lasting Radiolabeled Somatostatin Analogue 177Lu-DOTA-EB-TATE in Patients with Advanced Metastatic Neuroendocrine Tumors: A Phase 1 First-in-human Study,” Jingjing Zhang, MD,PhD, Yuejuan Cheng, MD,Hao Wang, MD, Jie Zang, PhD, Fang Li, MD, Chunmei Bai, MD, and Zhaohui Zhu, MD, Peking Union Medical College Hospital; Gang Niu, MD, Orit Jacobson, PhD4, and Xiaoyuan Chen, PhD, U.S. National Institutes of Health, Bethesda, MD.SNMMI’s 65th Annual Meeting, June 23-26, Philadelphia. Link to SNMMI Abstract
Cancer is a growth industry …literally! More people are being diagnosed than ever before. Fortunately, more people are surviving than ever before. This is against a backdrop of better awareness, better screening in the big population cancers, and to a certain extent better diagnostic tools, all of which is leading to earlier diagnosis.
So how does this affect Neuroendocrine Cancer?
According to the latest SEER database figures for Neuroendocrine Cancer, one reason for the 7 fold increase in incidence rates since the 1970s is all of those things above including better diagnostics. This has led to a revised set of epidemiological information in many countries that have made the effort to accurately update their cancer registries and there are consistent reports of incidence rates way beyond the recognised rare thresholds. Another piece of good news is that the increase in NET incidence is also due to earlier diagnosis. To sum that up – NETs is also a growth industry.
Combined with more awareness and education (including the important pathologists), more NETs than ever are being found, and many found earlier. However, it’s not party time yet because there remains far too many misdiagnoses due to the low population of the disease and the difficulty in diagnosing it. I want to focus on scanning (thus the title of the article). Whilst there are really important factors involved in a diagnosis, such as tumor and hormone markers, and biopsies (tissue is the issue), a scan is very frequently what triggers many deeper investigations to unearth a NET, i.e. if you can see it, you can normally detect it (whatever the ‘it’ is). And I include the widespread availability and increasing advances in endoscopy/ultrasounds/cameras which have also been instrumental in picking up many Gastrointestinal NETs.
The Gallium 68 PET Scan
There’s a lot of excitement about the Gallium 68 PET Scan since it was approved by the US FDA. It’s not new though and has been in use in several countries for some time. It’s a ‘nuclear scan’ and can often form part of what is known as a ‘Theranostic Pair’ (i.e. in conjunction with a therapy – read more here).
What does it do?
It comprises two main components – a PET scanning machine, and the use of a diagnostic imaging agent which is injected into the person undergoing the scan. Most machines have an inbuilt CT which forms part of the scan. The agent is a somatostatin analogue labeled radionuclide (Gallium 68) and basically the PET will then be used to see where the peptide/radionuclide mix ‘loiters’ (i.e. where there are concentrations of somatostatin receptors (SSTR) normally indicating ‘focal intense abnormality‘ of the type that is regularly found with NETs.
Imaging Agents. There are different agent variants, namely, DOTATATE, DOTATOC and DOTANOC. In USA, you may sometimes see this referred as NETSPOT which is more of a commercial label for the agent (NETSPOT is a DOTATATE). Ga68 PET or SSTR PET are common descriptors for the entire process regardless of the compound. Clearly the scan works best for those with ‘somatostatin receptor positive’ tumours.
These newer agents have several benefits over the elderly In111-pentetreotide (Octreotide scan), including improved detection sensitivity, improved patient convenience due to the 2-3 hour length of the study (compared to 2 or 3 days with Octreoscan), decreased radiation dose, decreased biliary excretion due to earlier imaging after radiotracer administration, and the ability to quantify uptake. The quantification of the uptake can help decide whether a patient is suitable for radionuclide therapy such as PRRT. Eventually, all Octreotide scans should be replaced with SSTR PET but it will take some time (and money).
To confirm the advantages of SSTR PET over Octreotide scans, a study comprising 1,561 patients reported a change in tumour management occurred in over a third of patients after SSTR PET/CT even when performed after an Octreotide scan. Worth pointing out that SSTR PET is replacing the ageing Octreotide scan and not conventional imaging (CI). You can see the recommended scenarios for use of SSTR PET in this article published by the Journal of Nuclear Medicine. The slide below is interesting, although it was a small study. However, you can see the treatment changes as a result of a Ga68 PET are quite striking.
Appropriate Use Criteria for Somatostatin Receptor PET Imaging in Neuroendocrine Tumors
I see many people complaining because the cannot get access to a Ga68 PET which is available through their healthcare system or local hospital. Many of these issues are insurance based. Worth pointing out that there are actually recommended usages for the Ga68 PET scan here. For example, it is not recommended for routine surveillance in place of Conventional Imaging (CI).
Any pitfalls with Ga68 PET Scan?
When you look at the study data above, it looks like an excellent addition to the diagnostic and surveillance toolkit for NETs. However, one of the challenges with modern scanning equipment and techniques is the ability to correctly interpret the results – in my opinion, this is almost as important as the efficiency of the machines and radionuclides. This requirement has been acknowledged in many articles and I particularly like this technical paper from a very experienced nuclear medicine physician Professor Michael Hofman from the Centre for Cancer Imaging at the Peter MacCallum Cancer in Melbourne. I had a chat with Professor Hofman who added that this is a very sensitive scan, so often picks up “new” disease, which isn’t really new, just never identifiable on standard imaging. However, there’s an excellent section on pitfalls in interpretation and I’m quoting an abstract below.
“Although GaTate PET/CT is a highly sensitive and specific technique for NETs, the attending physician or radiologist must be aware of various physiologic and other pathologic processes in which cellular expression of SSTR can result in interpretative error. Most of these processes demonstrate low-intensity and/or nonfocal uptake, in contrast with the focal intense abnormality encountered in NETs. Causes of interpretative pitfalls include prominent pancreatic uncinate process activity, inflammation, osteoblastic activity (degenerative bone disease, fracture, vertebral hemangioma), splenunculi or splenosis, and benign meningioma.”
“The highest-intensity physiologic uptake of GaTate is seen in the spleen, followed by the adrenal glands, kidneys, and pituitary gland”
It follows that failure to interpret nuclear scans alongside the patient’s clinical history can sometimes result in two big issues for patients:
1. Unnecessary worry when ‘something’ shows up which is actually a false positive.
2. Something which leads to irreversible treatment when it is was not required.
Just imagine something which is 40 times better than current PET scan technology? That’s what the scientists are working on now. Here’s an example called “EXPLORER“. You can update yourself here. The issue of interpretation will be even more difficult when the new generation of scans appear. There’s an excellent article from Cancer Research UK talking about the modern phenomenon called ‘overdiagnosis’ – readhere
Lanreotide and Octreotide and timing the scan?
From the same technical document referred above, here’s an extract (updated to include Lanreotide). “Uptake at physiologic and pathologic sites may change in patients who undergo concomitant short- or long-acting somatostatin analog therapy, which competes with the radiotracer for bioavailability. We generally discontinue short-acting octreotide for 12–24 hours and perform imaging in the week before the next dose of long-acting Octreotide/*Lanreotide, which is typically administered monthly“. It’s actually the same text as found in the manufacturer’s drug leaflet (click here). More evidence behind the reason for this restriction is found here (please refer to the comments on Ga68 PET – the article also covers the issue of PRRT which is very interesting as a separate subject to the scan timings).
*added by the author for completeness.
Having my first Ga68 PET Scan after 8 years of living with NETs?
When I was offered my very first Ga68 PET/CT at my recent 6 monthly surveillance meeting, I was both excited and apprehensive. I was diagnosed in 2010 and my staging was confirmed via an Octreotide Scan pointing out two further deposits (one of which has since been dealt with). I’ve had two further Octreotide Scans in 2011 and 2013 following 3 surgeries. The third scan in 2013 highlighted my thyroid lesion – still under a watch and wait regime. So far, my 6 monthly CT scans seemed to be adequate surveillance cover and my markers remain normal.
I’m apprehensive because of the ‘unknown’ factor with cancer – what is there lurking in my body that no-one knows about and which might never harm me.
I’m excited because it might just confirm that there is nothing new to worry about.
However, I’m both excited (morbidly) and apprehensive because the scan might find something potentially dangerous. As we know, NETs are mostly slow growing but always sneaky. That said, at least I will know and my medical team will know and be able to assess the risk and decide on a course of action.
Doing the Scan
On 5th June 2018, I attended a very experienced Ga68 PET establishment called Guys Cancer Centre in London. I arrived and was immediately taken under the wing of the nuclear medicine guys who asked me fairly in depth questions about my clinical background. They then inserted a cannula ready for the injection of the radiolabelled tracer. I was then installed in the ‘hot room’ where they injected the radionuclide tracer through the cannula and then I had to remain in the hot room for 1 hour to let the tracer circulate. After 1 hour, I was taken to the PET scanner and it took around 30-35 minutes. Following that I was allowed to leave for home. It was an extremely easy experience and a significant improvement on doing the 3 day Octreotide scan.
NANETS (North American Neuroendocrine Tumor Society) is one of the biggest NET conferences, bringing together NET Specialists from around the world to discuss state-of-the-art treatment modalities, new therapies, and ongoing controversies in the field of Neuroendocrine Neoplasms (Tumors and Carcinomas). This is fairly complex stuff but much of it will be familiar to many. I’ve filtered out several outputs from the conference which I think are both relevant and topical to patients. The list is below allowing you to easily peruse and read further via linkages if you need to read more. Remember, some of these are extracts so do not contain all the details of the research or study – although some of the linkages will take you to in-depth information if that’s your bag. Where applicable, I’ve also linked to some of my blog posts to add context and detail in patient speak. The list comprises articles which were published in medical news media and for which I received alerts. It does not comprise the entire schedule of NANETS 2017. I may add more to the list if other relevant and interesting articles are published downstream.
Please note: Some of the output from the conference is in ‘study form’ and has not yet been published as peer-reviewed data (important notice to readers).
NANETS to Bring All Specialties in the NETs Community Together for 10th Annual Symposium
Interview with Michael Soulen MD. Nice introduction.
PFS and OS After Salvage Peptide Receptor Radionuclide Therapy (PRRT) with 177-Lu[Dota⁰,Tyr³] octreotate in Patients with GastroEnteroPancreatic or Bronchial NeuroEndocrine Tumours (GEP-NETs) – The Rotterdam Cohort
What is Peptide Receptor Radionuclide Therapy (PRRT)?
For those who are still not sure what it’s all about. This is a non-surgical treatment which is normally administered intravenously. It’s based on the use of somatostatin receptors to attract a ‘radiopeptide’. The radiopeptide is a combination of a somatostatin analogue and a radioactive material. As we already know, somatostatin analogues (i.e. Lanreotide/Octreotide) are a NET cell targeting drug, so when combined radioactivity, it binds with the NET cells and delivers a high dose of targeted radiation to the cancer while preserving healthy tissue. In general, patients tend to receive up to 4 sessions spaced apart by at least 2 months.
PRRT will not work on all NETs and not everyone will suited to this treatment. In general, for this treatment to be more successful, you must have somatostatin receptors in your tumors. Success rates are not 100% – it should not be considered a cure or ‘magic bullet’. However, the results are said to be pretty good. The NETTER-1 trial data which has led to formal approval in Europe, USA and other areas, can be found here.
LATEST ON EXPANDED NETTER-1 TRIAL DATA. “Novartis has announced presentation of a new analysis of Lutathera (lutetium Lu 177 dotatate) NETTER-1 data at the 2018 European Society for Medical Oncology (ESMO) congress examining the impact of Lutathera treatment on patients with low, medium or high liver tumor burden. The data show that Lutathera treatment results in significant improvement in progression free survival (PFS) regardless of the extent of baseline liver tumor burden (LTB), elevated alkaline phosphatase (ALP) liver enzyme or presence of large (>30mm diameter) lesion in patients with progressive midgut neuroendocrine tumors (NETs) compared to octreotide LAR alone.”
Understanding the terminology is half the battle in understanding the latest developments. I’ve included Ga-68 PET scans within this section (or in more general terms Somatostatin Receptor PET (SSTR PET)) as the term ‘Theranostics‘ is becoming a commonly used theme. Theranostics is a joining of the words diagnostics and therapy.
LUTATHERA is the radionuclide ‘mix’ for use in Peptide Radio Therapy Treatment (PRRT). You may also see this drug called ‘Lutetium’ or ‘Lu-177 dotatate’, or just ‘Lu-177’ on its own. Yttrium 90 (Y-90) is a radionuclide also used in PRRT.
NETSPOT (USA) or SOMAKIT TOC (Europe) is not PRRT but it is the commercial names for the radiopeptide used in Gallium 68 (Ga-68) PET diagnostic scans.
Together they form a ‘theranostic pair’. Theranostics is apt as together (NETSPOT / SOMAKIT TOC and Lutathera), both target NETs expressing the same somatostatin receptor, with Lutathera intended to kill tumor cells by emitting a different kind of low-energy, short-range radiation than that of the diagnostic version.
Moreover, thanks to the theranostic approach that nuclear medicine allows, Novartis/AAA’s NETSPOT/SomaKit TOC products will be able to determine when Lutathera is the appropriate treatment.
Of course, this therapy has been in use in Europe and some other places for some time but to be honest, they have been on a limited scale and never formally approved by national drug agencies. Despite its extensive use, the EU approval in 2017 was actually the very first approval of PRRT anywhere in the world. For example, in UK, it was used for some time for those in need but was removed from routine availability through a ‘slush fund’ formally known as the Cancer Drugs Fund – to cut a long story short, the funding source was cut off, although there are still ways of obtaining the treatment pending formal acceptance by the NHS (certain criteria apply).
In the meantime, I constantly see stories of patients travelling to Switzerland, Germany, Netherlands, Sweden, Great Britain and others; mostly at their own cost. However, it does indicate one thing, there is a huge unmet need in that many patients do not have access to the best treatments in their own country. I see this daily through many private messages.
What about Grade 3 (High Grade) Neoplasms?
The main treatment for Grade 3 is chemotherapy, particularly poorly differentiated. PRRT tends to work better with efficient somatostatin receptors (i.e. somatostatin receptor-positive tumors). The European approval wording only covers Grades 1 and 2. The US FDA approval indicates “somatostatin receptor-positive tumors”. It’s also worth noting that with Grade 3, are more likely to exist in Grade 3 well differentiated NETs, particularly in the lower Ki-67 readings. However, there’s an interesting study from Australia which might be useful to read – check out the abstracthere (note the full version is not available free).
Merkel Cell Carcinoma. Although not indicated for this type of Neuroendocrine Neoplasm, there is evidence to suggest that this skin Neuroendocrine Carcinoma does express somatostatin receptors. Read more here.
What about Pheochromoctyoma/Paraganglioma?
There’s actually still a trial for Pheochromocytoma/Paraganglioma (Pheo/Para). It is known that Pheo/Para can have somatostatin receptor tumors so a useful trial. The aim of the trial is to assess the safety and tolerability. You can read about the trial here.
Where can I get PRRT?
Where can I get PRRT?
The aim of this section is to update on a regional basis in order to inform an international community of followers and readers.
I wanted a place to review what is happening globally given my following. In many countries, however, I’m dependent on feedback from patients in those countries. Please note this is not intended to be a 100% complete breakdown on everything about PRRT or PRRT centres – it’s a summary. It should be clear from below but please bear that in mind when reading.
This section of this article will cover each region, indicating where PRRT can be obtained (as far as I know). It is not designed to indicate whether this is through public or private facilities (this will depend to too many factors beyond the reach of this article). Please note this is not intended to be a 100% complete breakdown on every single PRRT centre – it’s a summary. This actually should be clear from below but please bear that in mind when reading.
On 29 August 2018. National Institute for Health Care Excellence (NICE) England has formally published that Lutetium (177Lu) oxodotreotide, within its marketing authorisation, is an option for treating unresectable or metastatic, progressive, well-differentiated (grade 1 or grade 2), somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumours (NETs) in adults. CLICK HERE to read the approval. Currently available in London and Liverpool. The Christie Mancheter is advertising it on their website and there is anecdotal talk of Newcastle and Leicester going live soon. I await the rollout of PRRT – watch this space for a table listing.
On 9 July 2018. The Scottish Medicines Consortium (NICE equivalent) has approved lutetium 177Lu (Lutathera) for patients in NHS Scotland. Good news for Scotland once their hospitals have the capability to deliver. Scottish patients would then not need to travel to England for the NHS Scotland funded treatment. Read more here.
It is funded in Wales and Northern Ireland but is currently administered in England with inter NHS budget transfers.
On 7th Feb 2019, Health Canada approved Lutathera™ (lutetium (177Lu) oxodotreotide) for the treatment of unresectable (not removable by surgery) or metastatic, well-differentiated, somatostatin receptor-positive (expressing the somatostatin receptor) gastroenteropancreatic neuroendocrine tumors (GEP-NETs) in adults with progressive disease. The treatment was previously available on a trial basis. Read more here.
Site update to follow but the following trial locations may be up and running first:
PRRT was approved in USA on 26 Jan 2018.The approval is for the treatment of somatostatin receptor positive gastroenteropancreatic neuroendocrine tumors (GEP-NETs), including foregut, midgut, and hindgut neuroendocrine tumors in adults. CLICK HERE.
The extended access program (trial) is no longer offered but these locations should be ahead of the game in terms of provision, notwithstanding insurance and provision of sufficient nuclear material.
In the meantime, known USA sites offering routine “live site” insurance based PRRT treatment are as follows – please note information has been gleaned from US patients due to no other consolidated source of this information being readily available. It’s possible some patients got mixed up between trial locations and live locations so let me know of any omissions or additions/corrections – thanks in advance.
DRAFT – NOT YET COMPLETE – (as at 20 Sep 2018)
Due in Service?
Dr Boris Naraev
UCSF Medical Center Mission Bay San Francisco
California – Antioch
Kaiser Permanente Antioch Medical Center
Cedars Sinai Medical Center LA
Stanford Medical Center
Kaiser Permanente Los Angeles Medical Center
Hoag Hospital Newport Beach
Kaiser Santa Clara Medical Center
City of Hope LA
Yale New Haven Medical Center
Rocky Mountain Cancer Center Denver
Dr Eric Liu
University of Colorado UC Health Denver
University of Miami
Winter Park, Florida Radiation Oncology Orlando
David Diamond MD
CCTA Newnan, Atlanta
Queen’s Medical Center
Dr. Marc Coel
Rush University Chicago
Xavier M. Keutgen, MD
The University of Chicago Medicine
Loyola University Medical Center Maywood
Indiana University Health
University of Iowa
Dr T O’Dorisio
University of Kansas Medical Center Fairway
University of Kentucky, Markey Cancer Center
John Hopkins Baltimore
Dana Farber Boston
Massachusetts General Hospital
Detroit – Karmanos Cancer Center
26 Apr 2018
Dr. Thor Halfdanarson
University of Minnesota Health
Sara Canon Cancer Center Kansas City
Siteman Cancer Center St. Louis/Barnes Jewish Hospital St. Louis
Dr Samuel Mehr
Nebraska Cancer Specialists Omaha
Dr Samuel Mehr
Lenox Hill NYC
Roswell Park Buffalo
The James, Columbus
Oregon Health & Science University (OHSU)
Fox Chase Philadelphia
Dr Paul Engstrom
Rhode Island Hospital Providence
Dr Paul Engstrom
MD Anderson Houston
Excel Diagnostics Houston
CHI St Lukes Houston
Huntsman Cancer Institute, Salt Lake City
Carilion Clinic Roanoke
Virginia Mason Seattle
Dr. Hagen Kennecke
VMedStar Georgetown University Hospital
VMU Cancer Institute Morgantown
Shalu Pahuja, M.D
UW Health Madison, Carbone Cancer Center
Noelle K. LoConte, MD Specialty: Medical Oncology Primary Location: UW Carbone Cancer Center (608) 265-1700 (800) 323-8942
Europe (EU affiliated countries)
The European Medicines Agency (EMA) “market authorisation” received a positive indication on 20th July followed by EC approval on 29 Sep 2017. The positive indication reads “Lutathera is indicated for the treatment of unresectable or metastatic, progressive, well differentiated (G1 and G2), somatostatin receptor positive gastroenteropancreatic neuroendocrine tumours (GEP NETs) in adults”. Of Course, the decision to fund the drug will be with national approval organisations. Whilst I’m sure there are many more, these well-known centres have been making PRRT available for some years (but please note there are others):
Netherlands – Rotterdam Treatment Centre – click here
Netherlands – the combined NET centres of the UMCU Utrecht and AVL Amsterdam have an ENET certification and they both do PRRT.
Denmark – ‘Rigshospitalet’ since 2009. They have treated around 250 patients- and given 800 treatments.
I’d be interested to hear from countries in Europe with their full list of centres or a link to it.
Australia seems to be ahead of the game or that is what I sense when I read output from there. There’s a good section on the Australian effort – click here.
These guys have had to fight to get some progress on the provision of PRRT. Currently New Zealanders have to go to Melbourne Australia for treatment – almost 50 New Zealanders with NETs are currently raising tens of thousands of dollars to pay for treatment in Australia because the life-prolonging treatment isn’t available locally. But this could change in 2018. Unicorn Foundation New Zealand announced that Pharmac, the New Zealand government agency that decides which pharmaceuticals, have said that PRRT will be funded for patients with medium priority for the treatment of unresectable or metastatic, well-differentiated NETs (irrespective of primary site) that express somatostatin receptors.
Lebanon – The American Hospital of Beirut – Dr Ali Shamseddine “We have started using Lu-177 here in Lebanon. So far, we have treated 3 patients, with good response. The operational cost is much less than in Europe”.
India – Mahatma Gandhi Cancer Hospital, Visakhapatnam. Recently started radionuclide therapy. Although only currently available privately, some patients have been sponsored by the companies that they work for. Point of contact is Dr. K. Raghava Kashyap. I’ve been assured by CNETS India that many locations have PRRT capability – contact them direct please.
There’s a lot of inaccurate and out of date information out there. Some of it is propaganda but most is a combination of misunderstanding and patient forum myth spreading …….
Myth 1: All Neuroendocrine Tumours are benign
Not true. By any scientific definition, the word ‘tumour’ means ‘an abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumours may be benign (not cancerous), or malignant (cancerous)’. Sure, some NETs will be benign. However, The World Health Organisation (WHO) 2010 classification for digestive system is based on the concept that all NETs have malignant potential, and has therefore abandoned the division into benign and malignant NETs and tumours of uncertain malignant potential. This has been reinforced in the 2017 update to include clarification for other endocrine organ types of NET including Pheochromocytoma. Read more here. The word ‘Carcinoid’ is inextricably linked with this issue – read here why we need to stop using the term to help fight the benign myth.
Myth 2: Neuroendocrine Tumours is a terminal condition
Not true. By any definition of the word terminal in a medical diagnostic context, most NET patients have a good prognostic outlook, even those with metastatic and incurable variants of the disease. Read more here.
Myth 3: Carcinoid is another word for Neuroendocrine Tumours
Not true. Carcinoid is a very old term and was phased out years ago. Carcinoid is not mentioned in the latest WHO Classification schemes for Neuroendocrine Neoplasms (a term covering Neuroendocrine Tumours and Neuroendocrine Carcinoma). Unfortunately, the problem is exacerbated by organisations and individuals who still use the word. Also, those who use the following terms:
“Carcinoid and Neuroendocrine”,
“Neuroendocrine and Carcinoid”,
“Carcinoid NETs” or “CNET”
These are all contextually incorrect and misleading terms (not to mention the bad grammar). ENETS, NANETS and NCCN publications are gradually phasing the word out except in relation to Carcinoid Syndrome (and even then there could be easy solutions for this). Read more here and here.
Myth 4: All NET patients get ‘carcinoid syndrome’
Not true. Firstly, many NET cancers are non-functional; and secondly, carcinoid syndrome is only one of a number of “NET Syndromes” associated with the various types of NET. However, the issue is further confused by those who use the word ‘Carcinoid‘ to incorrectly refer to all NETs and use Carcinoid Syndrome to refer to all NET Syndromes. Read more here.
Not true. Steve Jobs had a Neuroendocrine Tumour of the Pancreas. Ditto for a few other famous names. Read more here.
Myth 7: I’m not getting chemotherapy, I must be doing OK?
Not true. For some cancers or some sub-types of cancers, although it remains an option, chemotherapy is not particularly effective, e.g. some types of Neuroendocrine Cancer (NETs). In general, well differentiated NETs do not normally show a high degree of sensitivity to chemotherapy, although some primary locations fare better than others. However, many of the treatments for NET Cancer are somewhat harsh, have long-term consequences, and have no visible effects. NET patients are often said to “look well” but that doesn’t mean they are not struggling behind the scenes or under the surface. Read more here. P.S. Afinitor (Everolimus), Sutent (Sunitinib) are not chemo – Read more here.
Myth 8: All diarrhea is caused by carcinoid syndrome
Not true. It could be one of the other syndromes or tumor types or a side effect of your treatment. Check out this post.
Myth 9: Neuroendocrine Tumours is a ‘good cancer’
Not true. Simply, no cancer is good. Some are statistically worse than others in prognostic terms, that’s true…… but living with NETs is very often not a walk in the park. However, no one cancer is better to get than any other – they’re all bad. Read more here.
Myth 10: Every NET Patient was misdiagnosed for years
Not true. Many NET Patients are correctly diagnosed early on in their investigation and in a reasonable time. This myth is perpetuated because of two things: firstly, on forums, the ratio of long-term misdiagnosis is high creating a false perception; and secondly, the method of capturing patient surveys is not extensive enough – again creating a false perception. In fact, the latest and largest database analysis from US indicates earlier diagnosis is improving, with more and more NETs being picked up at an early stage. Read more here.
Myth 11: Somatostatin Analogues are a type of Chemotherapy
Not true. Somatostatin Analogues (e.g. Octreotide and Lanreotide) are not chemotherapy, they are hormone inhibiting drugs. They are more biotherapy. As the drugs latch onto somatostatin receptors, they are more targeted than systemic. For the record, Everolimus (Afinitor) and Sunitinib (Sutent) are not chemotherapy either. Read more here.
Myth 12: Stuart Scott (ESPN) and Audrey Hepburn had Neuroendocrine Cancer.
Not true. This is a common misunderstanding within the community. They both had Pseudomyxoma Peritonei (PMP). Read more about PMP here.
Myth 13: I’ve been diagnosed with Neuroendocrine Tumours – my life is over
Not true. Many patients live a very long time and lead fairly normal lives with the right treatment and support. It’s difficult but I try not to use ‘I can’t’ too much. Read more here.
Myth 14: There are only a handful of Neuroendocrine specialists in the world
Not true. There are many specialists in many countries. Get links to specialists by clicking here.
Myth 15: The Ga68 PET scan is replacing the CT and MRI scan in routine surveillance for all NET Patients
Not true. It is actually replacing the Octreotide Scan for particular purposes, or will eventually. Read more by clicking here.
Myth 16: All NET Patients are Zebras
Not true. They are in fact human beings and we should treat them as such. Please don’t call me a zebra and please don’t use the term on my social media sites, I refuse to perpetuate this outdated dogma.
Myth 17: Multiple Endocrine Neoplasia (MEN) is a type of Neuroendocrine Tumour
Not true. Multiple Endocrine Neoplasia are syndromes and inherited disorders. You can have MEN and not have any tumours. However, these disorders can put people at more risk of developing Neuroendocrine or Endocrine Tumours. Read morehere
Myth 18: Palliative Care means end of life or hospice care
Not true. Palliative care is specialized medical care that focuses on providing patients relief from pain and other symptoms of a serious illness. A multidisciplinary care team aims to improve quality of life for people who have serious or life-threatening illnesses, no matter the diagnosis or stage of disease. Read more here
Myth 19: Serotonin is found in foods
Not true. Serotonin is manufactured in the body. Read more here
Myth 20: NETs cannot be cured
Not true. If caught early enough, some NETs can be treated with curative intent (totally resected) with little or no further follow up. It says this in ENETS and NANETS publications which are authored by our top specialists. If we can’t believe them, who can we believe? Read more here.
Myth 21: Pancreatic Enzyme Replacement Therapy (Creon etc) is only for pancreatic patients
Not true. It’s for any patient who is exhibiting exocrine pancreatic insufficiency. Read more here.
More to follow no doubt
For general cancer myths and the dangers of fake health news, please see my ARTICLE HERE
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I recently wrote a blog called Neuroendocrine Cancer – Exciting Times Ahead! I wrote that on a day I was feeling particularly positive and at the time, I wanted to share that positivity with you. I genuinely believe there’s a lot of great things happening. Don’t get me wrong, there’s a lot still to be done, particularly in the area of diagnosis and quality of life after being diagnosed. However, this is a really great message from a well-known NET expert.
In an interview with OncLive, Jonathan R. Strosberg, MD, associate professor at the H. Lee Moffitt Cancer Center in Florida, discussed his presentation on NETs at a recent 2016 Symposium, and shed light on the progress that has been made in this treatment landscape.
OncLive: Please highlight some of the main points from your presentation.
Strosberg: The question I was asked to address is whether we’re making progress in the management of NETs, and I think the answer is unequivocally yes. Prior to 2009, there were no positive published phase III trials.
Since then, there have been 8 trials, 7 of which have reached their primary endpoints. So it’s been a decade of significant improvement. And even though none of these studies were powered to look at overall survival as an endpoint, we’re certainly seeing evidence of improvement in outcomes.
OncLive: What are some of the pivotal agents that you feel have impacted the paradigm in the past several years?
Strosberg: The first group is the somatostatin analogs. We use them to control hormonal symptoms like carcinoid syndrome, but with the CLARINET study, we now know that they substantially inhibit tumor growth.
The next significant drug we use in this disease is everolimus (Afinitor), an oral mTOR inhibitor, which is now approved in several indications based on positive phase III studies. The first was in pancreatic NETs and subsequently, based on the RADIANT-4 trial, it was also approved in lung and gastrointestinal NETs. So that was an important advance.
The next important category of treatment is radiolabeled somatostatin analogs, otherwise known as peptide receptor radiotherapy. The one that’s been tested in a phase III trial is lutetium dotatate, also known as Lutathera. It was tested in patients with progressive midgut NETs and showed a very substantial 79% improvement in progression-free survival, and a very strong trend toward improvement in overall survival, which we hope will be confirmed upon final analysis.
OncLive: Are we getting better at diagnosing and managing the treatment of NETs?
Strosberg: Certainly. I think pathologists are better at making the diagnosis of a NET, rather than just calling a cancer pancreatic cancer or colorectal cancer. They’re recognizing the neuroendocrine aspects of the disease, and doing the appropriate immunohistochemical staining.
We also have better diagnostic tools. We used to rely primarily on octreoscan, and in many cases we still do, but there is a new diagnostic scan called Gallium-68 dotatate scan, also known as Netspot, which has substantially improved sensitivity and specificity. It’s not yet widely available, but it is FDA approved and hopefully will enable better diagnosis as well as staging in the coming years.
And, with the increase in number of phase III studies, we’re developing evidence-based guidelines, which will hopefully lead to more standardization, although knowing how to sequence these new drugs is still quite challenging.
OncLive: With sequencing, what are the main questions that we’re still trying to answer?
Strosberg: If we take, for example, NETs of the midgut, beyond first-line somatostatin analogs, physicians and patients often face decisions regarding where to proceed next, and for some patients with liver-dominant disease, liver-directed therapies are still an option.
For others, everolimus is a systemic option, and then hopefully lutetium dotatate will be an option based on approval of the drug, which is currently pending. Knowing how to choose among those 3 options is going to be a challenge, and I think there will be debates. Hopefully, clinical trials that compare one agent to another can help doctors make that choice. It’s even more complicated for pancreatic NETs. Beyond somatostatin analogs, we have about 5 choices—we have everolimus, sunitinib (Sutent), cytotoxic chemotherapy, liver-directed therapy, and peptide receptor radiotherapy. It’s even more challenging in that area.
OncLive: Are there any other ongoing clinical trials with some of these agents that you’re particularly excited about?
Strosberg: There’s a trial that is slated to take place in Europe which will compare lutetium dotatate with everolimus in advanced pancreatic NETs, and I think that’s going to be a very important trial that will help us get some information on both sequencing of these drugs, as well as the efficacy of Lutathera in the pancreatic NET population, based on well-run prospective clinical trials. I’m particularly looking forward to that trial.
OncLive: Looking to the future, what are some of the immediate challenges you hope to tackle with NETs?
Strosberg: One area of particular need is poorly differentiated neuroendocrine carcinomas. That’s a field that’s traditionally been understudied. There have been very few prospective clinical trials looking at this particular population, and we’re hoping that will change in the near future. There are a number of trials taking place looking at immunotherapy drugs. If these agents work anywhere in the neuroendocrine sphere, they are more likely to work in poorly differentiated or high-grade tumors, in my opinion, given the mutational profile of these cancers. So that’s something I’m particularly looking forward to being able to offer these patients something other than the cisplatin/etoposide combination that goes back decades, and is of short-lasting duration.
See more at: http://www.onclive.com/publications/oncology-live/2016/vol-17-no-24/expert-discusses-recent-progress-in-net-management#sthash.ypkilX2A.dpuf
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Theranostics is a joining of the words therapeutics and diagnostics. You may also see it conveyed as ‘Theragnostics’ and these terms are interchangeable. The basic aim of theranotistics is to find and then destroy the ‘bad guys‘. With Neuroendocrine Cancer, finding the tumours (the bad guys) can often be a challenge – they can be small and/or difficult to find – they are sometimes expert at camouflage. Moreover, once found, they can then be difficult to treat (destroy), as they can often prove resistant to conventional cancer drugs and many are inoperable due to sheer quantity, spread and positioning. When they are found and identified, it’s also really helpful to know from the intelligence gathered, how successful the destroy (therapeutic) part of the mission might be.
The nuclear scan uses the same nuclear material as the therapy, therefore if you cancer lights up on the nuclear scan, then the therapy will find its way to the cancer and hopefully work well. That is the beauty of theranostic pairing, i.e. the use of the same agent in the diagnostics – the ability to find, estimate likely success criteria and then hopefully destroy – or at least reduce the capability of the tumours and extend life.
A great example of an approved Theranostic Pairin Neuroendocrine Cancer, is the combination of the Somatostatin Receptor based Ga68 PET scan using NETSPOT or SomaKit TOC™ (US/Europe respectively) and Peptide Receptor Radiotherapy (PRRT) using Lutathera which both target NETs expressing the same somatostatin receptor, with PRRT intended to kill tumor cells by emitting a different kind of low-energy, short-range radiation than that of the diagnostic version. As mentioned above, the Ga68 PET scan can give a reasonably indication of therapeutic success using PRRT based on measurements taken during the scan (too complex for this article).
Nuclear medicine makes it possible by using the same molecular targeting compound to create diagnostic and therapeutic drugs, which work as theranostic pairings. Advanced Accelerator Applications’ theranostic platform is based on radiolabelling a single targeting molecule with either gallium Ga-68 for diagnostic use or lutetium Lu-177 for therapeutic use. AAA’s pipeline now includes several theranostic drug pairings for oncology indications including prostate and breast cancer; and gastrointestinal stromal tumors (GIST).
THERANOSTICS – FIND
Newer imaging agents targeting somatostatin receptors (SSTR) labelled with 68 Ga have been developed, namely, DOTATATE, DOTATOC and DOTANOC. They are collectively referred to as SSTR PET.
The main difference among these three tracers (DOTA-TOC, DOTA-NOC, and DOTA-TATE) is their variable affinity to SSTR subtypes. All of them can bind to SSTR2 and SSTR5, while only DOTA-NOC shows good affinity for SSTR3.
These agents have several benefits over In111-pentetreotide (Octreotide scan), including improved detection sensitivity, improved patient convenience due to the 2 hour length of the study (compared to 2 or 3 days with Octreoscan), decreased radiation dose, decreased biliary excretion due to earlier imaging after radiotracer administration, and the ability to quantify uptake. The quantification of the uptake can help decide whether a patient is suitable for PRRT. Eventually, all Octreotide scans should be replaced with SSTR PET. To confirm the advantages of SSTR PET over Octreotide scans, a study comprising 1,561 patients reported a change in tumour management occurred in over a third of patients after SSTR PET/CT even when performed after an Octreotide scan. Worth pointing out that SSTR PET is replacing the ageing Octreotide scan and not conventional imaging (CI). You can see the recommended scenarios for use of SSTR PET in this article published by the Journal of Nuclear Medicine
Ga68 PET scans have been in many locations for some time. Current excitement is focused on USA locations with Ga68 PET (NETSPOT) only recently approved (DOTATATE). Other countries/scan centres may use one of the other types of imaging agent.
Read much more about this scan in my detailed article on Ga68 PET here.
So SSTR PETs above have the ability to find and estimate likely success criteria for therapy. We are now in a position to move on to ‘THERApy’ – e.g. Peptide Receptor Radiotherapy or PRRT.
THERANOSTICS – DESTROY
Lutathera® (note the ‘THERA’ which makes up the brand name)
Europe Approval: LUTATHERA®(lutetium (177Lu) Oxodotreotide) is indicated for the treatment of unresectable or metastatic, progressive, well differentiated (G1 and G2), somatostatin receptor positive gastroenteropancreatic neuroendocrine tumours (GEPNETs) in adults.
USA Approval: LUTATHERA® (lutetium Lu 177 dotatate) is indicated for the treatment of somatostatin receptor-positive gastroenteropancreatic neuroendocrine tumors (GEP-NETs), including foregut, midgut and hindgut neuroendocrine tumors in adults.
For commercial purposes, the drug may be slightly different on a regional basis. For all intents and purposes it does the same job.
PRRT with LUTATHERA®
LUTATHERA® solution for infusion is a ‘radiolabelled somatostatin analog (SSA)’ comprised of a radionuclide (Lutetium-177) and a peptide (differs between Europe and USA)
The relevant SSA binds with high affinity to the somatostatin receptors (SSTR) overexpressed in malignant neuroendocrine cells such as the ones found in GEP-NETs.
Lutetium-177 is a β particle emitting radionuclide, with a mean penetration range of 0.67 millimetres in tissue (maximum penetration range of 2.2 mm) which is sufficient to kill targeted tumour cells with a limited effect on neighbouring normal cells.
The affinity for SSTRs and the specificity of binding ensures a high level of specificity in the delivery of radiation to the tumour. Before starting treatment with LUTATHERA®, imaging must confirm the presence of these receptors in tumour tissues.
As an example of how the drug is administered, please watch this short video from the European site:
Please see the following post for a summary of PRRT activity worldwide. Please note this linked article is not designed to contain a list of every single location or country available – please bear that in mind when you read it – CLICK HERE
OPINION – nothing in here should be taken as advice from the author.
On paper, surgery remains the only potentially ‘curative‘ option for Neuroendocrine Tumours (NETs) but there are stage, grade and anatomical constraints to that opinion. Many people get ‘twitchy’ about any inference of the ‘C word’ (cure) but our most eminent NET specialists use the term frequently including in the major treatment guidelines.
I use the word ‘curative’ with some reservations because for many who are diagnosed at an advanced stage, surgery will not cure but will debulk or cytoreduce as much tumour as possible in order to palliate symptoms and improve quality of life. This is a big deal because NETs is one of a small number of cancers where debulking surgery can often provide a survival advantage for metastatic cases. One of the reasons it’s a big deal is because with more aggressive cancers at an advanced stage, surgery just might not be offered. It follows that surgery is most likely adding to the fairly decent NETs survival statistics, including for those with metastatic disease at diagnosis. More on this below.
That’s a fairly simplistic explanation on behalf of surgery. However, as we all know, nothing in Neuroendocrine Cancer is simple. There are always a number of factors involved and every decision can in some way be on an individual basis. There are guidelines for treatment of most types of NETs but ……. they are just that – guidelines. NET Centres and NET Specialists are encouraged to use these guidelines, for example, a European Centre of Excellence has ENETS Guidelines. There is a North American equivalent set published by NANETS and NCCN have a decent complementary set. The UK and Ireland guys (UKINETS) also published a set although many UK centres are ENETS accredited.
Whether to cut or not to cut (or watch and wait then cut if necessary) and the sequencing of treatments is a really difficult issue for NET specialists. I quite liked watching these two video clips and they cover this issue quite nicely including some interesting abdominal challenges in surgery from known NET Specialists – these short video sessions are highly recommended:
a. Risk Stratification and Management of NETs – click here
Surgery can sometimes be a tough call (……to cut or not to cut?)
It is an area where I have some sympathy for physicians and surgeons who sometimes have tough decisions to make. Surgery is risky, particularly where people are presenting in a weak condition, perhaps with very advanced disease, secondary illness and comorbidities. I also suspect age is a factor (I was surprised to find myself considered ‘young’ at 55). Physicians and surgeons need to weigh up these risks and the consequences of the surgery against a ‘watch and wait’ or alternative non-surgical approach. This would normally be discussed via a ‘Tumor Board’ or Multi-Disciplinary Team (MDT) meeting. However, and although imaging helps, the situation is not really 100% clear until the surgeon ‘gets inside’. Remember, all physicians and surgeons are bound by the ‘Hippocratic oath’ of “Do no harm“. Sometimes with NETs, it’s a tough call not only before they go inside but whilst they’re inside.
Surgery should be a carefully considered treatment (…..think before cutting?)
I read many stories from many different parts of the world and I also hear them from people who contact me privately on a daily basis. Some of them are perplexed why they are not receiving surgery and some are not entirely happy with the surgery they received. Many are perplexed by different advice from different doctors. I find it very difficult to respond to many. My most frequent answer is “ask your doctor” but I’m normally pretty helpful with the sorts of questions to ask.
One thing which tends to surprise people is speed – or lack of it! With lower grade NETs, the extent of the tumour (stage), its metastases, histological grade and secretory profile should be determined as far as possible before planning treatment. I like to remind people that in 2010, it took from 26 July to 9 Nov before my body saw a scalpel. With Grade 1/2 well differentiated NETs, you can often get away with that gap. Sometimes when you are diagnosed with NET, it’s a case of ‘hurry up and wait’.
Back to the guidelines, of course most people will probably fit reasonably well into the relevant guidelines flow chart. A very generic example here (not for active use please, your area may have an alternative based on availability of treatments etc):
If you search long and hard, you will find articles about whether to “cut or not to cut”. Not just a dilemma for NETs but also for many cancer types. During my research, I found there’s some overlap between this conundrum and the issue of “overdiagnosis”. By “overdiagnosis”, I mean the unnecessary declaration and treatment of something which would probably not harm a person whilst they live. This is a bit of a modern phenomena as diagnostic tools and screening programmes become more sophisticated and more sensitive …..something to consider with Ga68 PET scans as they are more widely used. If you search for ‘overdiagnosis’ you will see many articles, in particular (and as an example), with many Thyroid diagnoses. In another example, I read an article about Rectal cancerwhere the author suggested a ‘wait and see’ approach might be better for most. Worth adding at this point that many autopsies show up NETs in areas such as the appendix (…..more often than you think) – check out my article “Benign vs Malignant” and The Invisible NET Patient Population. When I attended ENETS 2017 and 2018, I heard many ‘experts’ talk about conservative approaches. However, I also heard many talk about aggressive approaches. Another term I see a lot is “one surgeon’s inoperable is another’s operable”.
Timing of Surgery (……to cut now, to cut later?)
Following on from the scenario above, timing of surgery can be another factor in a ‘watch and wait’ situation. I guess this might be something in the back of the minds of more cautious doctors when faced with a rather indolent and very slow growing Neuroendocrine Tumour. For some this can be a sensible thing – ‘kicking butt’ in a surgical context is sometimes the wrong approach. The worry is that if they are not a NET specialist, they may not fully understand the vagaries of neuroendocrine tumor behaviour (i.e. they all have malignant potential – WHO 2010/2017). We’ve all heard the stories of people being told it’s not cancer, right? Please note my article Benign vs Malignant. However, you may be interested in this post from someone who is one of the most experienced NET surgeons on the planet. Dr Eric Liu talks quite candidly about the ‘timing’ of surgery suggesting a ‘watch and wait’ approach in certain scenarios.
Of course cutting now might actually be a pre-emptive measure. For example, if physicians can see a growth which is critically placed close to an important structure such as a blood vessel or the bile duct or bowel. Even if the disease cannot be cured, removing the tumour may prevent problems in the future by removing disease from key areas before the vital structure has been damaged or blocked. For example, my surgeon conducted a high risk operation on some desmoplasia (serotonin fibrosis) which had encircled my aorta and cava almost occluding the latter. There’s an excellent surgery pamphlet from NET Patient Foundation and I strongly recommend a read as it’s an experienced surgeon’s approach to surgery with NETs (actually written by my own surgeon Mr Neil Pearce!). Click here to read it.
One NET centre in USA has published very detailed surgical statistics indicating that surgical cytoreduction in NET patients has low morbidity and mortality rates and results in prolonged survival. Their conclusion went on to say “We believe that surgical cytoreduction should play a major role in the care of patients with NETs”. You can read the extract from this document by clicking here. Authors: Woltering et al.
Was Steve Jobsa smart guy who made a stupid decision when it came to his health? It might seem so, from the broad outlines of what he did in 2003 when a CT scan and other tests found a cancerous tumour in his pancreas. Doctors urged him to have an operation to remove the tumour, but Mr. Jobs put it off and instead tried a vegan diet, juices, herbs, acupuncture and other alternative remedies. Nine months later, the Neuroendocrine Tumour had grown. Only then did he agree to surgery, during which his doctors found the cancer had spread to his liver. The rest is summarised in my article Steve Jobs.
This is a difficult subject and no one size fits all. Treatment for NETs can be very individual including surgery. I guess you need to be comfortable with your team. I was lucky, in that I lived close to a NET Centre. I was referred to their surgical team once my staging and grading were complete and I was stabilised on somatostatin analogues (carcinoid syndrome under control). I realise it’s difficult for many but I always say to people who make contact, it’s best if you can be seen by a NET centre or an experienced NET specialist – at least be guided by one if not possible or practical. Personally, I think the surgeon’s experience in dealing with NETs is really important. But even experienced NET centres/specialists have to make tough calls.
You may benefit from my 10 Questions article which also has links to NET Specialists.
I spend a lot of time talking about the most common forms of Neuroendocrine Tumours (NETs), but what about the less well-known types? As part of my commitment to all types of NETs, I’d like to shine a light on two less common tumour types known as Pheochromocytomas and Paragangliomas – incidence rate approximately 8 per million per year. They are normally grouped together and the definitions below will confirm why. If you think it’s difficult to diagnose a mainstream NET, this particular sub-type is a real challenge.
So, let’s get definitions out of the way:
Pheochromocytomas (Pheo for short)
Pheochromocytomas are tumours of the adrenal gland that produce excess adrenaline. They arise from the central portion of the adrenal gland, which is called the adrenal medulla (the remainder of the gland is known as the cortex which performs a different role and can be associated with a different tumour type). The adrenal medulla is responsible for the normal production of adrenaline, which our body requires to help maintain blood pressure and to help cope with stressful situations. The adrenal glands are situated on top of the kidneys (i.e. there are two). Adrenaline is also called ‘epinephrine’ which is curiously one of the 5 E’s of Carcinoid Syndrome.
Paragangliomas (Para for short)
Paragangliomas are tumours that grow in cells of the ‘peripheral’ nervous system (i.e. the nerves outside the brain and spinal cord). Like Pheochromocytomas, they can release excess adrenaline. There can be confusion between the two types of tumour as Paragangliomas are often described as extra-adrenal Pheochromocytomas (i.e. a Pheo external to the adrenal gland).
Going forward, I’m going to talk about both using the single term of ‘Pheochromocytoma’ in the context of an adrenaline secreting tumour but may refer to Paraganglioma where there might be a difference other than anatomical location.
Pheochromocytomas are often referred to as the “ten percent tumour” because as a rule of thumb they do many things about ten percent of the time. However, these figures are slowly changing, so this label is gradually becoming less apparent. The following is a fairly exhaustive list of these characteristics:
A few facts about Pheochromocytomas
As much as 1 in 3 are Malignant but most have undetermined biologic potential. A recent document issued by the World Health Organisation (WHO) stated that “Paragangliomas should not be termed benign”.
Around 10% of Pheochromocytomas are Bilateral (i.e. found in both adrenal glands: 90% arise in just one of the two adrenal glands)
Around 10% are Extra-Adrenal (found within nervous tissue outside of the adrenal glands … i.e. 10% are Paragangliomas)
Around 10% are found in Children (i.e. 90% in adults)
Up to 30% are Familial potentially rising to 50% for metastatic cases and Multiple Endocrine Neoplasia (MEN) involvement.
The recurrence rate is around 16%, i.e. about 1 in 6 patients have a tumor that comes back after surgery. Tumors that come back also have the potential to be malignant. If you have pheo or para and have surgery to remove it, be sure to continue to check in with your doctor to monitor for any returning tumors.
Present with a stroke (10% of these tumours are found after the patient has a stroke)
The classic symptoms of Pheochromocytomas are those attributable to excess adrenaline production. Often these patients will have recurring episodes of sweating, headache, and a feeling of high anxiety.
Headaches (severe)(one of the classic triad, see below)
Excess sweating (generalized)(one of the classic triad, see below)
Racing heart (tachycardia and palpitations)(one of the classic triad, see below)
Anxiety and nervousness
Nervous shaking (tremors)
Pain in the lower chest or upper abdomen
Nausea (with or without vomiting)
According to the ISI Book on NETs (Woltering, Vinik, O’Dorisio, et al), Pheochromocytomas present with a classic triad of symptoms and signs: headache, palpitations and sweating. This symptom complex has a high specificity and sensitivity (>90%) for the diagnosis of Pheochromocytomas. The figure is much lower in individual symptom presentations (palpitations 50%, sweating 30%, headaches 20%). In addition to correctly diagnosing from these symptoms, Pheochromocytomas may also be found incidentally during a surgical procedure even after a diagnosis of an ‘adrenal incidentaloma’
Markers. Like serotoninsecreting tumours, adrenal secreting tumours convert the offending hormone into something which comes out in urine. In fact, this is measured by 24 hour urine test very similar to 5HIAA (with its own diet and drug restrictions). It’s known as 24-hour urinary catacholamines and metanephrines. This test is designed to measure production of the different types of adrenaline compounds that the adrenal glands make. Since the body gets rid of these hormones in the urine, we simply collect a patient’s urine for 24 hours to determine if they are over-produced. Like 5HIAA, there is also a plasma (blood draw) version of the test. According to the ISI Book on NETs, there is also an additional test called ‘Vanillylmandelic Acid (VMA). This reference also indicates the most sensitive test is plasma free total metanephrines. Also read more here.
Genetics. The familial connection with Pheo/Para is complex. Up to 13 genes have been identified including NF1, RET, VHL, SDHA, SDHB, SDHC, SDHD, SDHAF2(SDH5), TMEM127, MAXm EPAS1, FH, MDH2. Read more here ( recent update). The NIH also have a useful section –click here.
Scans. Other than the usual range of scanners, ultrasound, CT/MRI, all of which may be used to find evidence of something, the other scan of note is called MIBG. This is a nuclear scan similar in concept to the Octreotide Scan given to many NET patients (in fact some Pheo patients my get an Octreotide scan if they have somatostatin receptors). The key differences with MIBG is the liquid radioactive material mix which is called iodine-123-meta-iodobenzylguanidine or 131-meta-iodobenzylguanidine (this is where the acronym MIBG originates). Together with the markers above, the results will drive treatment. Depending on availability, the latest PET scans may also be available potentially offering greater detail and accuracy i.e. 18F-FDOPA, 18F-FDG and Ga68. Read more on scans here.
This statement and diagram was provided by Dr Mark Lewis who is an Oncologist and MEN patient. “The algorithm for working up a hyperadrenergic state is attached (and was developed by Dr. Young at Mayo Clinic). It outlines the most reliable testing for a pheo or Paraganglioma”
Additional Factors and Considerations
This is an awareness post so I’m not covering treatment options in any detail except to say that surgery if often used to remove as much tumour as possible. Somatostatin Analogues may also be used in certain scenarios in addition to other hormone suppression or symptom controlling drugs. That said, Pheo/Para patients may be interested in a PRRT trial exclusively for Pheo/Para – read more here (see section entitled – “What about Pheo/Para”)
The adrenal cortex mentioned above is actually the site for Adrenocortical Carcinoma (ACC) – this is a totally different cancer.
Pheochromocytomas are probably difficult to diagnose (you only have to look at the symptoms to see that). The differential diagnoses (i.e. potential misdiagnoses) are: hyperthyroidism, hypoglycaemia, mastocytosis, carcinoid syndrome, menopause, heart failure, arrhythmias, migraine, epilepsy, porphyria lead poisoning, panic attacks and fictitious disorders such as the use of cocaine and benzedrine.
Many Pheochromocytoma patients will also be affected by Multiple Endocrine Neoplasia (MEN), in particular MEN2 (there are some wide-ranging percentage figures online for this aspect). There can also be an association with Von Hippel-Lindau (VHL) syndrome and lesscommonly with Neurofibromatosis type 1.
Given the nature of the hormones involved with Pheochromocytomas, there is a risk of intraoperative hypertensive crises. This is similar in some ways to Carcinoid Crisis but needs careful consideration by those involved in any invasive procedure.
Newly Approved Drug – AZEDRA
On 30th July 2018, Progenics Pharmaceuticals Announces FDA Approval for AZEDRA® (iobenguane I 131) to Treat Unresectable, Locally Advanced or Metastatic Pheochromocytoma or Paraganglioma – read more by clicking here.
Pheochromocytomas are very complex involving many of the challenges found in the more abundant and common types of NETs. To underscore this statement, please see this case studywhere one patient was misdiagnosed with psychiatric problems for 13 years before being correctly diagnosed with a metastatic Pheochromocytoma.
This is an extremely basic overview offered as an awareness message about the lesser known types of NETs. I refer you to my disclaimer. If you wish to learn more about Pheochromocytomas and Paragangliomas, check out the links below.
Scanning is a key diagnostic support and surveillance tool for any cancer. Even though you have elevated bloods or urine (….or not), a picture of your insides is really like a thousand words…. and each picture has a story behind it. Scanning can be a game changer in the hunt for tumours and although scans do not normally confirm the cancer type and grade, they certainly help with that piece of detective work and are key in the staging of the cancer.
When I read stories of people in a difficult diagnosis, I always find myself saying ‘a scan might resolve this’ and I always suggest people should try to get one. Even in the case of a story about late diagnosis or a misdiagnosis, I find myself thinking ‘if only they had done a scan earlier’. Despite what you read on NET forums, a CT scan will be able to find some evidence of tumour activity in 90-95% of cases. However, some are cunningly small or hiding and it can be like trying to find a needle in a haystack.
However, scans are not an exact science…..not yet! Apart from human error, sometimes tumours are too small to see and/or there are issues with ‘pickup’ (i.e. with NETs, nuclear scans need efficient somatostatin receptors). The differences between scan types are more quality (sensitivity) related as new technologies are introduced.
As for my own experience, I was very lucky. I managed to get a referral to a specialist early on in my diagnosis phase. He looked at the referral notes and said “what are you doing this afternoon“. I replied “whatever you want me to do“. He didn’t know I had cancer but his instincts led him to believe he needed to see inside my body, he wanted to scan me. The scan results were pretty clear – I had a metastatic Cancer and further checks were now needed to ascertain exactly what it was. So I took my seat on the roller coaster. Medicine is not an exact science (not yet anyway) but here’s something I believe is a very common occurrence in all cancers – If your doctors don’t suspect something, they won’t detect anything.
There’s frequent discussion about the best types of scans for different types of NETs and which is best for different parts of the anatomy. There’s also different views on the subject (including in the medical community), However, a few well known facts can be gleaned from authoritative NET sources:
Computed Topography (CT)
CT scans are often the initial imaging study for a patient presenting with signs or symptoms suggestive of many cancers including NET. These studies are most useful for disease staging and surgical planning as they provide excellent anatomic detail of the tumors themselves and surrounding structures. Primary NETs (GI and lung NETs) and their metastases are generally hyperenhancing with IV contrast and are best seen in the arterial phase of a triple phase CT scan.
In primary NETs, the average sensitivity of a CT scan is 73%. CT scans have even better sensitivity in detecting NET metastases, as they demonstrate 80% sensitivity for liver metastases (but see MRI below) and 75% sensitivity for other metastases (non-liver). This modality is also useful when the primary tumor site is unknown. In one single-institution retrospective study, it was the most common study ordered to look for an unknown primary tumor site and was able to uncover the primary in 95% of cases.
Magnetic resonance imaging (MRI)
MRI is the best conventional study to detail liver metastases in NETs. It is not as useful as CT for the detection of primary small bowel lesions or their associated lymphadenopathy, but is good for the detection of primary pancreatic NETs. A study comparing MRI, CT and standard somatostatin receptor-based imaging (OctreoScan) reported 95.2% sensitivity for MRI, 78.5% sensitivity for CT and 49.3% sensitivity for the OctreoScan in detecting hepatic metastases. MRI also detected significantly more liver lesions than the other two modalities.
You may see something called Magnetic Resonance Cholangiopancreatography (MRCP). Magnetic resonance cholangiopancreatography (MRCP) is a special type of magnetic resonance imaging (MRI) exam that produces detailed images of the hepatobiliary and pancreatic systems, including the liver, gallbladder, bile ducts, pancreas and pancreatic duct.
The primary role of conventional ultrasound in neuroendocrine disease is detection of liver metastases and estimation of total liver tumor burden. This technique has the advantages of near-universal availability, intraoperative utility, minimal expense and lack of radiation. Most examinations are performed without contrast, which limits their sensitivity (compared with CT and MRI). I know in my own situation, US was used as a quick check following identification of multiple liver metastasis during a CT scan. I’ve also had US used to monitor distant lymph nodes in the neck area but always in conjunction with the most recent CT scan output.
Endoscopic Ultrasound (EUS)
With increased access to endoscopy, NETs in the stomach, duodenum, and rectum are increasingly incidentally detected on upper endoscopy and colonoscopy. Patients are frequently asymptomatic without any symptoms referable to the a NET (i.e. non-functional). EUS has also been used to survey patients at increased risk of developing pancreatic NETs. For example, patients with multiple endocrine neoplasia (MEN). They are also frequently used in conjunction with biopsies using fine needle aspiration (FNA) guided by EUS.
18-Fluoro-Deoxy-Glucose PET (FDG PET) is used to detect malignancy for a variety of tumor types. Unfortunately, its utility has not been borne out in NETs, as the majority of NETs tend to be relatively metabolically inactive and fail to take up the tracer well. However, high-grade NETs are more likely to demonstrate avid uptake of 18FDG, giving these scans utility in identifying tumors likely to display more aggressive behavior.
The use of Fluoro-18-L-Dihydroxyphenylalanine (18F-FDOPA) in PET was developed in the 80’s for the visualisation of the dopaminergic system in patients with degenerative disorders, such as Parkinson’s Disease and related disorders. The ﬁrst publication on the use of 18F-FDOPA PET for brain imaging was in 1983, which was followed by many others on the use of 18F-FDOPA PET for the diagnosis of Parkinson’s disease. Years later, in 1999 the ﬁrst publication on the use of 18F-FDOPA PET for imaging of neuroendocrine tumour appeared. The value of 18F-FDOPA PET has now been proven for the diagnosis and staging of many neuroendocrine tumours, brain tumours and congenital hyperinsulinaemia of infants.
18F-FDOPA is accurate for studying well differentiated tumours. However the difficult and expensive synthesis have limited its clinical employment. It currently can be successfully used for imaging tumours with variable to low expression of somatostatin receptors (SSTR) such as Medullary Thyroid Carcinoma, Neuroblastoma, Pheochromocytoma), and others that cannot be accurately studied with Somatostatin SSTR scans such as the OctreoScan (Somatostatin Receptor Scintigraphy (SRS)), which uses the ligand 111In-DPTA-D-Phe-1-octreotide or the newer 68Ga DOTA-peptides.
Radioiodinated (123I) metaiodobenzylguanidine (MIBG) is an analog of norepinephrine that is used to image catecholamine-secreting NETs such as pheochromocytomas, paragangliomas and glomus tumors. It can also be used to look for Neuroblastoma in children. In patients with functional pheochromocytomas or paragangliomas, this modality has a sensitivity of 90% and positive predictive value of 100%. However, it has limited use in Gastrointestinal (GI) NETs, as this modality was positive in only 49.1% of patients. In the same cohort of patients, OctreoScan was positive in 91.2%. As an imaging tool, this study is best used to confirm a diagnosis of pheochromocytoma or paraganglioma and define the extent of metastatic disease in these tumors. (Note – the Ga68 PET is rising in prominence though). Its most practical use in GI NETs may be to determine whether patients with metastases may benefit from treatment with 131I-MIBG (a form of radiotherapy).
Somatostatin receptor-based imaging techniques
Somatostatin is an endogenous peptide that is secreted by neuroendocrine cells, activated immune cells and inflammatory cells. It affects its antiproliferative and antisecretory functions by binding to one of five types of somatostatin receptors (SSTR1- SSTR5). These are G-protein coupled receptors and are normally distributed in the brain, pituitary, pancreas, thyroid, spleen, kidney, gastrointestinal tract, vasculature, peripheral nervous system and on immune cells. Expression of SSTRs is highest on well-differentiated NETs. Somatostatin receptor type 2 is the most highly expressed subtype, followed by SSTRs 1 and 5, SSTR3 and SSTR4.
It must be noted that even the most modern scans are not an exact science. Radionuclide scans are like conventional imaging, they can be subject to physiological uptake or false positives, i.e. they can indicate suspicious looking ‘glows’ which mimic tumours. This article explains it better than I can – click here.
The ubiquity of SSTRs on NET cell surfaces makes them ideal targets for treatment (e.g. Somatostatin Analogues (Octreotide/Lanreotide) and PRRT), but also for imaging. There are two primary types of somatostatin receptor-based imaging available:
Octreoscan – In111 based
The most common (currently) is the OctreoScan or Somatostatin Receptor Scintigraphy (SRS), which uses the ligand 111In-DPTA-D-Phe-1-octreotide and binds primarily to SSTR2 and SSTR5. In its original form, it provided a planar, full body image. In modern practice, this image is fused with single photon emission computed tomography (SPECT) and CT. This takes advantage of the specificity of the OctreoScan and the anatomic detail provided by SPECT/CT, improving OctreoScan’s diagnostic accuracy. These improvements have been shown to alter the management in approximately 15% of cases, compared with just OctreoScan images. In primary tumors, the OctreoScan’s sensitivity ranges from 35 to 80%, with its performance for unknown primary tumors dipping beneath the lower end of that range (24%). Its ability to detect the primary is limited by the size but not SSTR2 expression, as tumors less than 2 cm are significantly more likely not to localize but do not have significantly different SSTR2 expression than their larger counterparts.
Octreoscan – Tc99m based
In one study, it was shown that sensitivity and negative predictive
values of Tc-99m-Octreotide scan is significantly higher than that of CT
and MRI. Using Tc-99m instead of In-111 had several advantages that
include better availability, cheaper and higher quality images. In
addition, to less radiation exposure to both patients and nuclear
medicine personnel. In the absence of Ga68 PET, this could prove a reliable alternative. Please note this scan is completed in a single day vs In111 Octreotide time of 2-3 days.
Ga68 PET (or SSTR PET in general)
The newest somatostatin receptor-based imaging modality, although it has been around for some time, particularly in Europe. The most common of these labeled analogs are 68Ga-DOTATOC, 68Ga-DOTANOC and 68Ga-DOTATATE. They may be known collectively as ‘SSTR-PET’. Additionally, the DOTATATE version may often be referred to as NETSPOT in USA but technically that is just the commercial name for the radionuclide mix.
These peptides are easier and cheaper to synthesize than standard octreotide-analog based ligands, boast single time point image acquisition compared to 2 or 3 days with Octreoscan. Its superior spatial resolution derives from the fact that it measures the radiation from two photons coincidentally. SPECT, in comparison, measures the gamma radiation emitted from one photon directly. This results in different limitations of detection – millimeters for 68Ga-PET compared with 1 cm or more for SPECT. There are a few choices of ligands with this type of imaging, but the differences lie primarily in their SSTR affinities – all of the ligands bind with great affinity to SSTR2 and SSTR5. 68Ga-DOTANOC also binds to SSTR3. Despite these differences, no single 68Ga ligand has stood out as the clear choice for use in NETs. As with standard somatostatin receptor-based imaging, these 68Ga-PET studies are fused with CT to improve anatomic localization.
Comparison studies between 68Ga-PET and standard imaging techniques (CT, OctreoScan) have universally demonstrated the superiority of 68Ga-PET in detection of NET primary tumors and metastases. Two early studies compared 68Ga-DOTATOC to standard somatostatin imaging (SRS)-SPECT and CT. Buchmann et al. reported that 68Ga-DOTATOC detected more than 279 NET lesions in 27 patients with histologically proven NETs, whereas SRS-SPECT detected only 157. The greatest number of lesions were detected in the liver. 68Ga-DOTATOC found more than 152 hepatic lesions, while SRS-SPECT found only 105, resulting in a 66% concordance rate between the two modalities. The concordance for abdominal lymph nodes was worse at 40.1%. Cleary these advantages are going to impact on treatment plans, some needing to be altered. In addition, 68Ga-DOTA PET imaging can be used to determine which patients might benefit from use of Somatostatin Analogues (Octreotide/Lanreotide) and PRRT – you can read more about this integrated and potentially personalised treatment in my article on ‘Theranostics‘ – click here.
It’s worth pointing out that SSTR PET is replacing previous types of radionuclide scans, mainly Octreoscan (Indium 111) and is not replacing conventional imaging (CI) such as CT and MRI etc. Whilst SSTR-PET has demonstrated better sensitivity and specificity than CI and In-111, there are specific instances in which SSTR-PET is clearly preferred: at initial diagnosis, when selecting patients for PRRT, and for localization of unknown primaries. For patients in which the tumor is readily seen on CI, SSTR-PET is not needed for routine monitoring. The Journal of Nuclear Medicine has just published “Appropriate Use Criteria for Somatostatin Receptor PETImaging in Neuroendocrine Tumors” which gives guidance on it’s use – issued by the Society of Nuclear Medicine and Molecular Imaging (SNMMI).
Parathyroid Scan – Sestamibi
Sestamibi scanning is the preferred way in which to localize diseased parathyroid glands prior to an operation. This parathyroid scan was invented in the early 1990’s and now is widely available. Sestamibi is a small protein which is labeled with the radio-pharmaceutical technetium99 (Tc99m). This very mild and safe radioactive agent is injected into the veins of a patient with hyperparathyroidism (parathyroid disease) and is absorbed by the overactive parathyroid gland. Since normal parathyroid glands are inactive when there is high calcium in the bloodstream, they do not take up the radioactive particles. When a gamma camera is placed over the patient’s neck an accurate picture will show the overactive gland. Only the overactive parathyroid gland shows up…a very accurate test.
The Sestamibi scan will display the hyperactive gland which is causing hyperparathyroidism in about 90 percent (90% sensitivity) of all patients. If the Sestamibi does show the hyperactive gland it is almost always correct (98-100% specificity). It takes approximately two hours to perform the Sestamibi scan after it has been injected. Pictures of the neck and chest are usually taken immediately after the injection and again in 1.75 to 2.0 hours (shown above). Newer techniques allow for more complete two and three dimensional images to be obtained of a patient’s neck. This technique is called SPECT scanning (Single Proton Emission Computerized Tomography) but it is usually not necessary.
Taking the camera inside and directly to the Tumour
Of course there are other ways to “see it” via several types of Endoscopy procedures – taking the camera to the tumour. Read my article about this by clicking here
A look to the future of PET Scans
Just imagine something which is 40 times better than current PET scan technology? That’s what the scientists are working on now. Here’s an example called “EXPLORER“. Clearly there are more answers required in order to see if this is suitable for use with NETs (i.e. will it work with our radionuclide tracers etc) but it is very exciting and like something out of Star Trek. A little bit of me is worried about ‘overdiagnosis’ so interpretation of something that detailed will be very important to avoid unnecessary worry. Read more here and there is a later update here. Check out this cool video of the 3D images:
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Scanning is a key diagnostic and surveillance tool for any cancer. Even though you have elevated bloods or urine (….or not), a picture of your insides is really like a thousand words…. and each picture has a story behind it. Scanning can be a game changer in the hunt for tumours and although scans can’t (yet) confirm the cancer type and grade, they certainly help with that piece of detective work and are key in the staging of the cancer.
When I read stories of people in a difficult diagnosis, I always find myself saying ‘a scan might resolve this’ and I always suggest people should try to get one. Even in the case of a story about late diagnosis or a misdiagnosis, I find myself thinking ‘if only they had done a scan earlier’. Despite what you read on NET forums, a CT scan will normally find some evidence of most tumour activity.
However, scans are not an exact science…..not yet! Apart from human error, sometimes tumours are too small to see and/or there are issues with ‘pickup’ (i.e. with NETs, nuclear scans need efficient somatostatin receptors). However, technology is improving all the time and you can read about this in my blog Neuroendocrine Cancer – Exciting times Ahead.
As for my own experience, I was very lucky. I managed to get a referral to a specialist early on in my diagnosis phase. He looked at the referral notes and said “what are you doing this afternoon”. I replied “whatever you want me to do”. He wanted to scan me. He didn’t know I had cancer but his instincts led him to believe he needed to see inside my body. The scan results were pretty clear – I had a metastatic Cancer and further checks were now needed to ascertain exactly what it was. So I took my seat on the rollercoaster. Here’s something I always say I believe is so much better than the impractical early diagnosis messages that seem to pervade our community: If your doctors don’t suspect something, they won’t detect anything and I believe this is a very frequent outcome of many diagnoses for many cancers (not just NETs).
There’s frequent discussion about the best types of scans for different types of NETs and even for different parts of the anatomy. This is correct and there’s also different views on the subject (including in the medical community), However, a few well known facts that can be gleaned from authortative NET sources. I found this useful video summary from the NET Patient Foundation describing the different scans for NET Cancer and what to expect. Worth a look.
Sooner we can all get access to the latest radionuclide scans the better!
In 2013, just when I thought everything seemed to be under control, I was told I had a ‘lesion’ on the left upper lobe of my thyroid. At the time, it was a bit of a shock as I had already been subjected to some radical surgery and wondered if this was just part of the relentless march of metastatic NET disease. The thyroid gland does in fact get mentioned frequently in NET patient discussions but many of the conversations I monitored didn’t seem to fit my scenario – cue relentless study! I’ve been meaning to write this blog for some time but here is a synopsis of my research translated into ‘patient speak’. This is intentionally brief, it’s a big subject. I’ll finish off with an update on where I am with my thyroid issue.
Where is the thyroid and what does it do?
Before I found out about my thyroid problem, I had absolutely no idea what its function was. I can tell you know, it’s a small organ but it has a massive job!
It lies in the front of your neck in a position just below your ‘Adam’s apple’. It is made up of two lobes – the right lobe and the left lobe, each about the size of a plum cut in half – and these two lobes are joined by a small bridge of thyroid tissue called the isthmus. It is sometimes described as butterfly shape. The two lobes lie on either side of your wind-pipe. The fact that it comes up a lot in NET patient discussions is hardly surprising as it’s an endocrine organ responsible for making two hormones that are secreted into the blood: Thyroxine (T4) and Triiodothyronine (T3). These hormones are necessary for all the cells in your body to work normally.
Do I have Thyroid Cancer?
I’ve had a number of biopsies on the thyroid lesion, several fine needle aspiration (FNA) and one ‘core’. The FNAs were generally inconclusive and the core confirmed fibrous tissue only. However, the general diagnosis is inconclusive and I have been labelled “THY3F”. Curiously this decodes to “an abnormality is present but it could either be a benign (non cancerous) growth or a malignant cancerous growth of the follicular cells. A quick primer on Thyroid Cancer is below if you’re interested.
The following is a list of facts regarding thyroid nodules:
Thyroid nodules are three times more common in women than in men
30% of 30-year-old women will have a thyroid nodule.
One in 40 young men has a thyroid nodule.
More than 95% of all thyroid nodules are benign (non-cancerous growths).
Some thyroid nodules are actually cysts, which are filled with fluid rather than thyroid tissue.
Purely cystic thyroid nodules (thyroid cysts) are almost always benign.
Most women will develop a thyroid nodule by the time they are 50 years old.
The incidence of thyroid nodules increases with age.
50% of 50-year-old women will have at least one thyroid nodule.
60% of 60-year-old women will have at least one thyroid nodule.
70% of 70-year-old women will have at least one thyroid nodule.
See EndocrineWeb for more detail about thyroid issues unrelated to NET.
There can be other issues with Thyroids including cancer and clearly this was my concern when the word ‘lesion’ was mentioned. At this point, it’s worth mentioning something from my cancer history which I initially assumed was related but it would appear to be a coincidence (for the time being …..). I also have a hotspot in my left supraclavicularfossa (SCF) lymph nodes (near the clavicle), geographically close to the thyroid (and my lesion is left-sided). 5 nodes were removed from this area in Feb 2012 for an exploratory biopsy which subsequently tested negative and CT and Ultrasound both show nothing vascular or pathologically enlarged. BUT …. there is still a hotspot showing on a subsequent Octreoscan since the nodes were removed in 2012. For the record, I also had positively tested nodes removed from my left axillary (armpit) during the same procedure (my distant disease has always been left-sided).
The surgeon who operated on my left axillary and SCF nodes also specialises in Thyroids and so it was an easy decision to ask to be referred to him. He explained that whilst he could just take the left lobe or the whole thyroid, it would mean lifelong treatment to add to my current burden and perhaps for something which will never trouble me. As nothing is palpable and I have no symptoms, I agreed to a ‘watch and wait’ approach. I now have regular tests and I saw him Endocrine MDT annually for a blood test review and ultrasound check (but see update below).
Latest update as at 15 Jan 2019
After monitoring for the first two years, my specialist was not happy with TSH/T4 blood results (elevated for the second time and also on a retest). On 20 March 2018, following an Endocrine appointment, I was put on a trial dose of 50mcg of Levothyroxine to counter the thyroid panel results indicating mild hypothyroidism. Levothyroxine is a thyroid hormone replacement. My subsequent two x thyroid panel results are back in the middle of the range so all is good. Am detecting a slight increase in available energy.
The results of my first Ga68 PET scan in June 2018 indicated some “uptake” but the report inferred it was physiological uptake (false positive). In fact, at my 2019 appointment, the thyroid lesion is slightly smaller on the latest ultrasound. I’m personally fairly certain this is not connected to NETs and my Endocrine MDT have now referred me back to be survellanced by the NET MDT, they remain on call for any issues.
What else can go wrong with a thyroid?
Apart from cancer, the main issues appear to be an underactive Thyroid or an overactive Thyroid – known respectively as Hypothyroidism (not enough thyroxine is produced for the body’s needs) and Hyperthyroidism (too much thyroxine is produced for the body’s needs). Of course, these issues can be caused or made worse by cancer.
Hypothyroidism – If too little of the thyroid hormones are produced, the cells and organs of your body slow down. If you become hypothyroid, your heart rate, for example, may be slower than normal and your intestines work sluggishly, so you become constipated. Key symptoms: tiredness, feeling cold, weight gain, poor concentration, depression. Some of these symptoms look familiar? The word ‘hashimoto’s’ also comes up on patient forums frequently – this is related to hypothyroidism (underactive).
Hyperthyroidism – If too much of the thyroid hormones are secreted, the body cells work faster than normal, and you have Hyperthyroidism. If you become hyperthyroid because of too much secretion of the hormones from the thyroid gland, the increased activity of your body cells or body organs may lead, for example, to a quickening of your heart rate or increased activity of your intestine so that you have frequent bowel motions or even diarrhoea. Key symptoms – weight loss, heat intolerance, anxiety, and, sometimes, sore and gritty eyes. Hmm, again, some of these look familiar?
Check out this excellent short video from WebMD – click here or the picture below. It’s based on USA but most of it is relevant globally.
It’s also worth noting that somatostatin analogues might cause a “slight decrease in Thyroid function” (it actually states words to this effect in the Lanreotide and Octreotide patient leaflets). Thus why I advise you not to be underactive with your Thyroid surveillance – read more click here
Routine ‘Thyroid blood tests’ from your doctor will confirm whether or not you have a thyroid disorder. I now test for TSH (thyroid-stimulating hormone), T3 and T4 every 6 months. My levels are back to normal ranges since being prescribed thyroid hormone replacement therapy.
Remember: Hypo is ‘underactive’, Hyper is ‘overactive’. Sometimes there are very few symptoms.
Also worth mentioning something called the ‘Parathyroid’ as these glands can frequently be related to NET Cancer (see my blog on Multiple Endocrine Neoplasia(MEN)). It’s another subject in its own right but I just wanted to emphasise that this is a totally different organ with a totally different function (it regulates Calcium). They are located adjacent to the Thyroid, thus the term ‘para’.
Quick primer on Thyroid Cancer
There are a number of different types of Thyroid Cancer
Papillary thyroid cancer is the most common type of thyroid cancer, accounting for about 80% of thyroid cancers. While papillary thyroid cancer typically occurs in only one lobe of the thyroid gland, it may arise in both lobes in up to 10% to 20% of cases. Papillary thyroid cancer is most common in women of childbearing age. It sometimes is caused by exposure to radiation. Even though papillary thyroid cancer is usually not an aggressive type of cancer, it often metastasizes (spreads) to the lymph nodes in the neck. Papillary thyroid cancer treatment usually is successful.
Follicular thyroid cancer accounts for about 10% of thyroid cancers. Like papillary thyroid cancer, follicular thyroid cancer usually grows slowly. Its outlook is similar to papillary cancer, and its treatment is the same. Follicular thyroid cancer usually stays in the thyroid gland but sometimes spreads to other parts of the body, such as the lungs or bone. However, it usually does not spread to lymph nodes. It is more common in countries where diets do not contain enough iodine.
There is a type of thyroid tumour which has recently been removed as a type of cancer. “Encapsulated follicular variant of papillary thyroid carcinoma” is now known as “noninvasive follicular thyroid neoplasm with papillary thyroid-like nuclear features” or NIFTP. The word ‘carcinoma’ has gone. Read about this here.
Hurthle cell carcinoma, also called oxyphil cell carcinoma, is a type of follicular thyroid cancer. Most patients diagnosed with Hurthle cell cancer do well, but the outlook may change based on the extent of disease at the time of diagnosis.
Medullary thyroid cancer (MTC) is the only type of thyroid cancer that develops in the parafollicular cells of the thyroid gland. It accounts for 3% to 10% of thyroid cancers. Medullary cancer cells usually make and release into the blood proteins called calcitonin and/or carcinoembryonic antigen, which can be measured and used to follow the response to treatment for the disease. Sometimes medullary cancer spreads to the lymph nodes, lungs or liver before a nodule is found or the patient has symptoms. MTC can be treated more successfully if it is diagnosed before it has spread. There are two types of MTC:
Sporadic MTC is more common, accounting for 85% of medullary thyroid cancers. It is found mostly in older adults and is not inherited.
Familial MTC is inherited, and it often develops in childhood or early adulthood. If familial MTC occurs with tumours of certain other endocrine organs (parathyroid and adrenal glands), it is called multiple endocrine neoplasia type 2 (see my blog on MEN 2).
Anaplastic thyroid cancer is the most dangerous form of thyroid cancer. It is makes up only 1% of thyroid cancers. It is believed that anaplastic thyroid cancer grows from a papillary or follicular tumour that mutates further to this aggressive form. Anaplastic thyroid cancer spreads rapidly into areas such as the trachea, often causing breathing difficulties. Anaplastic thyroid cancer sometimes is called undifferentiated thyroid cancer because the cells are so different from normal thyroid tissue.
Thyroid cancer is not very common but diagnoses are ‘skyrocketing’ most likely due to advanced detection techniques. Most are very slow-growing with 5 year survival of 97% according to MD Anderson. There is a very interesting article about the overdiagnosis of Thyroid cancer which I found useful given my situation. You can read it here.
Thyroid ‘nodules’ would appear to be very common with 50-70% of all 50-70 year olds having at least one nodule present and statistically, 95% of these are benign (see EndocrineWeb
“I’m only as good as my last scan”. I received this comment last week in response to one of my posts and I thought it was a very pragmatic thing for someone to say.
A NET patient under surveillance has regular tests at determined intervals but the one that is most likely to spot disease progression, stability or regression is a scan. Markers such as (say) Chromogranin A (CgA) or 5HIAA are clearly useful but in an ongoing surveillance scenario, they alone would not be used as a firm declaration of progression, stability or regression. Every picture tells a story and a scan is normally the confirmation required whether it’s a CT, MRI or PET (etc).
Scans are also important at the diagnostic phase and I’m sure like myself, many people had their first ever scan at this point. You can have many checks, investigations and tests but for most, the scan is normally the main test that is going to confirm the presence of tumours. This then leads to further checks to confirm the staging and grading (i.e. a biopsy) and then hopefully, a proper diagnosis.
I don’t mind scans, they are probably the test that is going to alert my team to anything odd going on. Thus why I don’t mind doing them – in fact, they are a piece of cake!
OPINION. When I was being officially told I had an advanced and incurable cancer, I did what most people seem to do on films/TV ….. I asked “how long do I have“. The Oncologist said ” … perhaps just months“. That must have been quite a shock because for a few moments after that, I heard nothing – my brain was clearly still trying to process those words – I wasn’t even feeling unwell! The really important bit I missed was him go on to say “…but with the right treatment, you should be able to live for a lot longer”. Fortunately, my wife Chris heard it all and I was refocused. “OK Doc – let’s go” I said. Always take someone with you to take notes at important meetings with Oncologists!
I continue to see quite a few posts and articles about death and dying and I noticed some patients were using the word ‘terminal‘ to describe Neuroendocrine Cancer, despite in some cases, having been diagnosed some years ago. This label is not just confined to use within Facebook forums, I’ve also seen this on wider social media including twitter, blogs and newspaper items. For some, this appears to be the prognosis given to them by their doctors. I find this surprising. However, I’m much less surprised to see many comments on forums from people who had been told the worst by their doctors but were still alive and kicking WAY beyond those worst case prognostic statements.
Definitions are important so what does ‘terminal cancer’ actually mean?
I’m conscious there are legal ramifications with the definitions (wills, life insurance, disability etc) and that these may differ on an international/federal basis. I therefore intentionally confined my searching to a couple of ‘big hitter’ and ‘authoritative’ sites:
Cancer Research UK defines terminal as “When cancer is described as terminal it means that it cannot be cured and is likely to cause death within a limited period of time. The amount of time is difficult to predict but it could be weeks to several months”.
The American Cancer Society defines terminal as “an irreversible condition (it cannot be cured) that in the near future will result in death or a state of permanent unconsciousness from which you are unlikely to recover. In most states, a terminal illness is legally defined as one in which the patient will die shortly whether or not medical treatment is given.”
Can terminal as defined above be applied to Neuroendocrine Cancer?
I’m sure it can, e.g. with very advanced and very aggressive disease and for any grade when taking into account the condition of the patient and other factors (secondary illnesses/comorbidities, refusal of treatment etc). Clearly, that is a terrible situation. I’m also conscious that some people do eventually die because of this disease or its consequences and that is also terrible.
How long is a piece of string?
I think with most Neuroendocrine Cancer patients, “how long do I have” can be a tough question to answer. Thinking back to my own situation, although it was an obvious question to ask my Oncologist, I can see it might have caught him unawares. I suspect he was erring on the side of caution as I don’t believe he had formulated my treatment plan ….. i.e. my case had not yet been looked at by a Multi-Disciplinary Team (MDT), a bit like a ‘Tumor Board’. I had already been confirmed Grade 2 (via liver biopsy) and my CT scans were indicating widespread disease. I was yet to have an Octreotide scan and the conventional biochemical markers (CgA and 5HIAA). I suspect, faced with my question, he went for the worst case, based on the statistics he had access to at the time. What I now know is that, in the year of my diagnosis, the median survival was 33 months in patients with advanced Grade 1/Grade 2 NETs with distant metastasis. These statistics are certainly better today but my Oncologist was probably on the right track. However, at no time did he use the word ‘terminal’.
The Cancer story is changing
What I also found during my research is that as more and more people in the UK are now living with cancer (all cancer) rather than dying from it, there is a new class of patients emerging – Macmillan UK call this “treatable but not curable” and I believe this is very relevant to Neuroendocrine Cancer. I touched on this in an awareness blog entitled “Living with Neuroendocrine Cancer – it takes guts“. You will find some data in this blog about a major increase in the amount of people with cancer who eventually die of something else (…… basically it has doubled). For many, Cancer is no longer a death sentence. I do accept that it can be difficult to live with certain cancers and this is also covered in my “it takes guts” blog linked above.
Survivorship and Hope
You can find numerous examples of long-term survivors of advanced Neuroendocrine Tumours on the ‘airwaves’, many with a relatively good quality of life (QoL). I don’t normally pay much attention to prognostic data, I take my lead from the huge number of patients living a long time with Neuroendocrine Cancer. However, I was particularly interested to read a set of USA statistics from NOLA (Boudreaux, Woltering et al) which said “Our survival of stage IV midgut NET patients that we performed surgical debulking on was published in the Journal of the American College of Surgeons in 2014. It showed our 5, 10 and 20-year survival rates were 87%, 77% & 41% respectively. It’s also worth noting the comparison with the 2004 SEER database analysis which listed the 5 & 10 year SEER survival at 54% and 30% respectively”. Clearly, the NOLA figures are guidelines (and only for midgut) but they do seem to reflect my previous statement about seeking out positives rather than dwelling on the negatives. The SEER 2012 figures are much better than the 2004 versions stating “Survival for all NETs has improved over time, especially for distant-stage gastrointestinal NETs and pancreatic NETs in particular, reflecting improvement in therapies.
Exciting times ahead
On the subject of therapy improvement, there has been a plethora of new treatments coming online and more entering and progressing through the approvals pipeline. Check out my article entitled Exciting Times Ahead. Also listen to a NET Expert along the same lines. PRRT is making a real difference.
Following my diagnosis in 2010, I went on to receive really good treatment and it continues to this day with Lanreotide backed up by a rigorous surveillance regime (and this is backed up by my own advocacy!). However, I have totally accepted the fact that I have metastatic Neuroendocrine Cancer and that it cannot be cured. By the way, I intentionally used ‘metastatic‘ rather than Stage IV. Mention of Stage IV can set off alarm bells and send the wrong message to the recipient. I don’t believe Stage IV has the same ‘red flag’ meaning for well-differentiated NETs as it does with more aggressive cancers of the same stage. Given what I know now, I would certainly challenge any doctor who told me I had a ‘terminal disease’ and at the same time told me I had a slow-growing well differentiated Neuroendocrine Cancer.
I now live with this disease (….and it’sconsequences) and do not feel like I’m dying of it. Moreover, I most certainly do not see myself as a ‘terminal’ cancer patient, particularly as I’ve now been living with it since 2010.
Until I was diagnosed with metastatic Neuroendocrine Cancer, I didn’t have a clue about hormones – it’s one of those things you just take for granted. However, hormones are vital to human health (male and female) and it’s only when things go wrong you suddenly appreciate how important they are ……..like a lot of other things in life I suppose! The presence of over-secreting hormones (often called peptides throughout) is useful to aid diagnosis albeit it often means the tumours have metastasized. It’s also a frequent indication that the person has an associated NET syndrome.
This is a really complex area and to understand the hormone problems associated with Neuroendocrine Cancer, you need to have a basic knowledge of the endocrine and neuroendocrine systems. I’ve no intention of explaining that (!) – other than the following high level summary:
Glands in the endocrine system use the bloodstream to monitor the body’s internal environment and to communicate with each other through substances called hormones, which are released into the bloodstream. Endocrine glands include; Pituitary, Hypothalmus, Thymus, Pineal, Testes, Ovaries Thyroid, Adrenal, Parathyroid, Pancreas.
A Hormone is a chemical that is made by specialist cells, usually within an endocrine gland, and it is released into the bloodstream to send a message to another part of the body. It is often referred to as a ‘chemical messenger’. In the human body, hormones are used for two types of communication. The first is for communication between two endocrine glands, where one gland releases a hormone which stimulates another target gland to change the levels of hormones that it is releasing. The second is between an endocrine gland and a target organ, for example when the pancreas releases insulin which causes muscle and fat cells to take up glucose from the bloodstream. Hormones affect many physiological activities including growth, metabolism, appetite, puberty and fertility.
The Endocrine system. The complex interplay between the glands, hormones and other target organs is referred to as the endocrine system.
The Neuroendocrine System. The diffuse neuroendocrine system is made up of neuroendocrine cells scattered throughout the body. These cells receive neuronal input and, as a consequence of this input, release hormones to the blood. In this way they bring about an integration between the nervous system and the endocrine system (i.e. Neuroendocrine). A complex area but one example of what this means is the adrenal gland releasing adrenaline to the blood when the body prepares for the ‘fight or flight’ response in times of stress, ie, for vigorous and/or sudden action.
Hormones – the NET Effect
At least one or more hormones will be involved at various sites and even within certain syndromes, the dominant and offending hormone may differ between anatomical tumour sites. For example, NETs of the small intestine, lung or appendix (and one or two other places) may overproduce serotonin and other hormones which can cause a characteristic collection of symptoms currently called carcinoid syndrome. The key symptoms are flushing,diarrhea and general abdominal pain, loss of appetite, fast heart rate and shortness of breath and wheezing. The main symptom for me was facial flushing and this was instrumental in my eventual diagnosis. The fact that I was syndromic at the point of diagnosis made it easier to discover, albeit the trigger for the investigation was a fairly innocuous event. Other types of NETs are also affected by the overproduction of hormones including Insulinomas, Gastrinomas, Glucagonomas, VIPomas, Somatostatinomas, and others. These can cause their own syndromes and are not part of carcinoid syndrome as some organisations incorrectly state. For more on NET syndromes – Read Here.
So are hormones horrible?
Absolutely not, they are essential to the normal function of the human body. For example if you didn’t have any of the hormone Serotonin in your system, you would become extremely ill. On the other hand, if your glands start secreting too much of certain hormones, your body could become dysfunctional and in some scenarios, this situation could become life threatening. So hormones are good as long as the balance is correct. NET patients with an oversecreting tumor may be classed as “functional”.
Functional tumors make extra amounts of hormones, such as gastrin, insulin, and glucagon, that cause signs and symptoms.
Nonfunctional tumors do not make extra amounts of hormones. Signs and symptoms are caused by the tumor as it spreads and grows. Many NET patients are deemed to be “non-functioning” with normal hormone levels. It’s also accurate to say that many can move from one stage to the other.
Location Location Location
It’s accurate to say that the type and amount of hormone secretion differs between locations or sites of the functional tumor and this can also create different effects. The division of NETs into larger anatomical regions appears to differ depending on where you look but they all look something likes this:
Foregut NETs: In the respiratory tract, thymus, stomach, duodenum, and pancreas. This group mostly lack the enzyme aromatic amino decarboxylase that converts 5-HTP (5-Hydroxytryptophan – a precursor to serotonin) to serotonin (5-HT); such tumours tend to produce 5-HTP and histamine instead of serotonin. The Pancreas is a particularly prominent endocrine organ and can produce a number of different syndromes each with their associated hormone oversecretion – although many can be non-functional (at least to begin with). Lung NETs rarely produce serotonin, but may instead secrete histamine causing an ‘atypical’ carcinoid syndrome with generalized flushing, diarrhea, periorbital oedema, lacrimation and asthma. They may also produce adrenocorticotropic hormone (ATCH) or corticotropin-releasing factor (CRP), resulting in an ectopic Cushing’s syndrome. Please note the respiratory tract and thymus are not really anatomically pure ‘Foregut’ – but in NETs, grouped there for convenience.
Midgut NETs: In the small intestine, appendix, and ascending colon. For example, serotonin secreting tumors tend to be associated with carcinoid syndrome which tends to be associated with midgut NETs and this is normally the case. Many texts will also tell you that a syndrome only occurs at a metastatic stage. Both are a good rule of thumb but both are technically incorrect. For example, ovarian NETs can have a form of carcinoid syndrome without liver metastasis (tends to be described as atypical carcinoid syndrome). It’s also possible to see serotonin secreting tumors in places such as the pancreas (although what you would call that type of NET is open for debate).
Hindgut NETs (transverse, descending colon and rectum) cannot convert tryptophan to serotonin and other metabolites and therefore rarely cause carcinoid syndrome even if they metastasise to the liver.
Less Common Locations – there are quite a few less common NET locations which may involve less common hormones – some are covered below including the key glands contributing to NETs.
Unknown Primary? – One clue to finding the primary might be by isolating an offending hormone causing symptoms.
The key NET hormones
I used the example of Serotoninabove because it is the most cited problem with NET Cancer although it does tend to be most prevalent in midgut tumors. Serotonin is a monoamine neurotransmitter synthesized from Tryptophan, one of the eight essential amino acids (defined as those that cannot be made in the body and therefore must be obtained from food or supplements). About 90% of serotonin produced in the body is found in the enterochromaffin cells of the gastrointestinal (GI) tract where it is used mainly to regulate intestinal movements amongst other functions. The remainder is synthesized in the central nervous system where it mainly regulates mood, appetite, and sleep. Please note there is no transfer of serotonin across the blood-brain barrier.
Alterations in tryptophan metabolism may account for many symptoms that accompany carcinoid syndrome. Serotonin in particular is the most likely cause of many features of carcinoid syndrome as it stimulates intestinal motility and secretion and inhibits intestinal absorption. Serotonin may also stimulate fibroblast growth and fibrogenesis and may thus account for peritoneal and valvular fibrosis encountered in such tumours; serotonin, however, it is said not to be associated with flushing. The diversion of tryptophan to serotonin may lead to tryptophan deficiency as it becomes unavailable for nicotinic acid synthesis, and is associated with reduced protein synthesis and hypoalbuminaemia; this may lead to the development of pellagra (skin rash, glossitis, stomatitis, confusion/dementia).
Serotonin is also thought to be responsible for ‘right sided’ heart disease (Carcinoid Heart Disease). It is thought that high levels of serotonin in the blood stream damages the heart, leading to lesions which cause fibrosis, particularly of the heart valves. This generally affects the right side of the heart when liver metastases are present. The left side of the heart is usually not affected because the lungs can break down serotonin. Right sided heart failure symptoms include swelling (edema) in the extremities and enlargement of the heart.
Whilst serotonin can be measured directly in the blood, it’s said to be more accurate to measure 5HIAA (the output of serotonin) via blood or urine, the latter is said to be the most accurate.
Tackykinins include Substance P, Neurokinin A, Neuropeptide K and others. They are active in the enterochromaffin cells of the GI tract but can also be found in lung, appendiceal and ovarian NETs, and also in Medullary Thyroid Carcinoma and Pheochromocytomas. They are thought to be involved in flushing and diarrhea in midgut NETs. The most common tachykinin is Substance P, which is a potent vasodilator (substances which open up blood vessels). Telangiectasias are collections of tiny blood vessels which can develop superficially on the faces of people who have had NETs for several years. They are most commonly found on the nose or upper lip and are purplish in color. They are thought to be due to chronic vasodilatation.
Histamine is a hormone that is chemically similar to the hormones serotonin, epinephrine, and norepinephrine. After being made, the hormone is stored in a number of cells (e.g., mast cells, basophils, enterochromaffin cells). Normally, there is a low level of histamine circulating in the body. However (and as we all know!), the release of histamine can be triggered by an event such as an insect bite. Histamine causes the inconvenient redness, swelling and itching associated with the bite. For those with severe allergies, the sudden and more generalized release of histamine can be fatal (e.g., anaphylactic shock). Mast cell histamine has an important role in the reaction of the immune system to the presence of a compound to which the body has developed an allergy. When released from mast cells in a reaction to a material to which the immune system is allergic, the hormone causes blood vessels to increase in diameter (e.g., vasodilation) and to become more permeable to the passage of fluid across the vessel wall. These effects are apparent as a runny nose, sneezing, and watery eyes. Other symptoms can include itching, burning and swelling in the skin, headaches, plugged sinuses, stomach cramps, and diarrhea. Histamine can also be released into the lungs, where it causes the air passages to become constricted rather than dilated. This response occurs in an attempt to keep the offending allergenic particles from being inhaled. Unfortunately, this also makes breathing difficult. An example of such an effect of histamine occurs in asthma. Histamine has also been shown to function as a neurotransmitter (a chemical that facilitates the transmission of impulses from one neural cell to an adjacent neural cell).
In cases of an extreme allergic reaction, adrenaline is administered to eliminate histamine from the body. For minor allergic reactions, symptoms can sometimes be lessened by the use of antihistamines that block the binding of histamine to a receptor molecule. Histamine is thought to be involved with certain types and locations of NET, including Lung and foregut NETs where they can cause pulmonary obstruction, atypical flush and hormone syndromes.
Histamine, another amine produced by certain NETs (particularly foregut), may be associated with an atypical flushing and pruritus; increased histamine production may account for the increased frequency of duodenal ulcers observed in these tumours.
Kallikrein is a potent vasodilator and may account for the flushing and increased intestinal mobility.
Although prostaglandins are overproduced in midgut tumours, their role in the development of the symptoms of carcinoid syndrome is not well established but triggering peristalsis is mentioned in some texts.
Bradykinin acts as a blood vessel dilator. Dilation of blood vessels can lead to a rapid heartbeat (tachycardia) and a drop in blood pressure (hypotension). Dilation of blood vessels may also be partly responsible for the flushing associated with carcinoid syndrome.
Gastrin is a hormone that is produced by ‘G’ cells in the lining of the stomach and upper small intestine. During a meal, gastrin stimulates the stomach to release gastric acid. This allows the stomach to break down proteins swallowed as food and absorb certain vitamins. It also acts as a disinfectant and kills most of the bacteria that enter the stomach with food, minimising the risk of infection within the gut. Gastrin also stimulates growth of the stomach lining and increases the muscle contractions of the gut to aid digestion. Excess gastrin could indicate a NET known as a Gastric NET (stomach) or a pNET known as Gastrinoma (see pancreatic hormones below).
Calcitonin is a hormone that is produced in humans by the parafollicular cells (commonly known as C-cells) of the thyroid gland. Calcitonin is involved in helping to regulate levels of calcium and phosphate in the blood, opposing the action of parathyroid hormone. This means that it acts to reduce calcium levels in the blood. This hormone tends to involve Medullary Thyroid Carcinoma and Hyperparathyroidism in connection to those with Multiple Endocrine Neoplasia. Worth also pointing out the existence of Calcitonin Gene-Related Peptide (CGRP) which is a member of the calcitonin family of peptides and a potent vasodilator. Please note that hypothyroidism is often a side effect of NETs or treatment for NETs – please click here to read about the connection.
HPA AXIS – It’s important to note something called the HPA axis when discussing pituitary hormones as there is a natural and important connection and rhythm between the Hypothalamus, Pituitary and the Adrenal glands. However, I’m only covering the pituitary and adrenal due to their strong connection with NETs.
Adrenocorticotropic hormone (ATCH) is made in the corticotroph cells of the anterior pituitary gland. It’s production is stimulated by receiving corticotrophin releasing hormone (CRH) from the Hypothalamus. ATCH is secreted in several intermittent pulses during the day into the bloodstream and transported around the body. Like cortisol (see below), levels of ATCH are generally high in the morning when we wake up and fall throughout the day. This is called a diurnal rhythm. Once ACTH reaches the adrenal glands, it binds on to receptors causing the adrenal glands to secrete more cortisol, resulting in higher levels of cortisol in the blood. It also increases production of the chemical compounds that trigger an increase in other hormones such as adrenaline and noradrenaline. If too much is released, The effects of too much ATCH are mainly due to the increase in cortisol levels which result. Higher than normal levels of ATCH may be due to:
Cushing’s disease – this is the most common cause of increased ATCH. It is caused by a tumor in the pituitary gland (PitNET), which produces excess amounts of ATCH. (Please note, Cushing’s disease is just one of the numerous causes of Cushing’s syndrome). It is likely that a Cortisol test will also be ordered if Cushing’s is suspected.
A tumour outside the pituitary gland, producing ATCH is known as an ectopic ATCH. With NETs, this is normally a pNET, Lung/Bronchial/Pulmonary NET or Pheochromocytoma.
Adrenaline and Noradrenline
These are two separate but related hormones and neurotransmitters, known as the ‘Catecholamines’. They are produced in the medulla of the adrenal glands and in some neurons of the central nervous system. They are released into the bloodstream and serve as chemical mediators, and also convey the nerve impulses to various organs. Adrenaline has many different actions depending on the type of cells it is acting upon. However, the overall effect of adrenaline is to prepare the body for the ‘fight or flight’ response in times of stress, i.e. for vigorous and/or sudden action. Key actions of adrenaline include increasing the heart rate, increasing blood pressure, expanding the air passages of the lungs, enlarging the pupil in the eye, redistributing blood to the muscles and altering the body’s metabolism, so as to maximise blood glucose levels (primarily for the brain). A closely related hormone, noradrenaline, is released mainly from the nerve endings of the sympathetic nervous system (as well as in relatively small amounts from the adrenal medulla). There is a continuous low-level of activity of the sympathetic nervous system resulting in release of noradrenaline into the circulation, but adrenaline release is only increased at times of acute stress. These hormones are normally related to adrenal and extra adrenal NETs such as Pheochromocytoma and Paraganglioma. Like serotonin secreting tumours, adrenal secreting tumours convert the offending hormone into something which comes out in urine. In fact, this is measured (amongst other tests) by 24 hour urine test very similar to 5HIAA (with its own diet and drug restrictions). It’s known as 24-hour urinary catacholamines and metanephrines. Worth noting that adrenaline is also known as Epinephrine (one of the 5 E’s of Carcinoid Syndrome).
This is a steroid hormone, one of the glucocorticoids, made in the cortex of the adrenal glands and then released into the blood, which transports it all round the body. Almost every cell contains receptors for cortisol and so cortisol can have lots of different actions depending on which sort of cells it is acting upon. These effects include controlling the body’s blood sugar levels and thus regulating metabolism acting as an anti-inflammatory, influencing memory formation, controlling salt and water balance, influencing blood pressure. Blood levels of cortisol vary dramatically, but generally are high in the morning when we wake up, and then fall throughout the day. This is called a diurnal rhythm. In people who work at night, this pattern is reversed, so the timing of cortisol release is clearly linked to daily activity patterns. In addition, in response to stress, extra cortisol is released to help the body to respond appropriately. Too much cortisol over a prolonged period of time can lead to Cushing’s syndrome. Cortisol oversecretion can be associated with Adrenal Cortical Carcinoma (ACC) which can sometimes be grouped within the NET family.
Other hormones related to ACC include:
Androgens (e.g. Testosterone) – increased facial and body hair, particularly females. Deepened voice in females.
Estrogen – early signs of puberty in children, enlarged breast tissue in males.
Aldosterone – weight gain, high blood pressure.
Adrenal Insufficiency (Addison’s Disease) occurs when the adrenal glands do not produce enough of the hormone cortisol and in some cases, the hormone aldosterone. For this reason, the disease is sometimes called chronic adrenal insufficiency, or hypocortisolism.
Parathyroid hormone (PTH) is secreted from four parathyroid glands, which are small glands in the neck, located behind the thyroid gland. Parathyroid hormone regulates calcium levels in the blood, largely by increasing the levels when they are too low. A primary problem in the parathyroid glands, producing too much parathyroid hormone causes raised calcium levels in the blood (hypercalcaemia – primary hyperparathyroidism). You may also be offered an additional test called Parathyroid Hormone-Related Peptide (PTHrP). They would probably also measure Serum Calcium in combination with these type of tests. The parathyroid is one of the ‘3 p’ locations often connected to Multiple Endocrine Neoplasia – MEN 1
Pancreatic Hormones (Syndromes)
Pancreatic neuroendocrine tumors form in hormone-making cells of the pancreas. You may see these described as ‘Islet Cells’ or ‘Islets of Langerhans’ after the scientist who discovered them. Pancreatic NETs may also be functional or non-functional:
Functional tumors make extra amounts of hormones, such as gastrin, insulin, and glucagon, that cause signs and symptoms.
Nonfunctional tumors do not make extra amounts of hormones. Signs and symptoms are caused by the tumor as it spreads and grows.
There are different kinds of functional pancreatic NETs. Pancreatic NETs make different kinds of hormones such as gastrin, insulin, and glucagon. Functional pancreatic NETs include the following:
Gastrinoma: A tumor that forms in cells that make gastrin. Gastrin is a hormone that causes the stomach to release an acid that helps digest food. Both gastrin and stomach acid are increased by gastrinomas. When increased stomach acid, stomach ulcers, and diarrhea are caused by a tumor that makes gastrin, it is called Zollinger-Ellison syndrome. A gastrinoma usually forms in the head of the pancreas and sometimes forms in the small intestine. Most gastrinomas are malignant (cancer).
Insulinoma: A tumor that forms in cells that make insulin. Insulin is a hormone that controls the amount of glucose (sugar) in the blood. It moves glucose into the cells, where it can be used by the body for energy. Insulinomas are usually slow-growing tumors that rarely spread. An insulinoma forms in the head, body, or tail of the pancreas. Insulinomas are usually benign (not cancer).
Glucagonoma: A tumor that forms in cells that make glucagon. Glucagon is a hormone that increases the amount of glucose in the blood. It causes the liver to break down glycogen. Too much glucagon causes hyperglycemia (high blood sugar). A glucagonoma usually forms in the tail of the pancreas. Most glucagonomas are malignant (cancer).
Pancreatic Polypeptide (PPoma). A pancreatic polypeptide is a polypeptide hormone secreted by the pancreatic polypeptide (PP) cells of the islets of Langerhans in the endocrine portion of the pancreas. Its release is triggered in humans by protein-rich meals, fasting, exercise, and acute hypoglycemia and is inhibited by somatostatin and intravenous glucose. The exact biological role of pancreatic polypeptide remains uncertain. Excess PP could indicate a pNET known as PPoma.
Other types of tumors: There are other rare types of functional pancreatic NETs that make hormones, including hormones that control the balance of sugar, salt, and water in the body. These tumors include:
VIPomas, which make vasoactive intestinal peptide. VIPoma may also be called Verner-Morrison syndrome, pancreatic cholera syndrome, or the WDHA syndrome (Watery Diarrhea, Hypokalemia (low potassium)and Achlorhydria).
Somatostatinomas, which make somatostatin. Somatostatin is a hormone produced by many tissues in the body, principally in the nervous and digestive systems. It regulates a wide variety of physiological functions and inhibits the secretion of other hormones, the activity of the gastrointestinal tract and the rapid reproduction of normal and tumour cells. Somatostatin may also act as a neurotransmitter in the nervous system.
Having certain syndromes can increase the risk of pancreatic NETs.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk with your doctor if you think you may be at risk. Multiple endocrine neoplasia type 1 (MEN1) syndrome is a risk factor for pancreatic NETs.
Signs and symptoms of pancreatic NETs
Signs or symptoms can be caused by the growth of the tumor and/or by hormones the tumor makes or by other conditions. Some tumors may not cause signs or symptoms. Check with your doctor if you have any of these problems.
Signs and symptoms of a non-functional pancreatic NET
A non-functional pancreatic NET may grow for a long time without causing signs or symptoms. It may grow large or spread to other parts of the body before it causes signs or symptoms, such as:
A lump in the abdomen.
Pain in the abdomen or back.
Yellowing of the skin and whites of the eyes.
Signs and symptoms of a functional pancreatic NET
The signs and symptoms of a functional pancreatic NET depend on the type of hormone being made.
Too much gastrin may cause:
Stomach ulcers that keep coming back.
Pain in the abdomen, which may spread to the back. The pain may come and go and it may go away after taking an antacid.
The flow of stomach contents back into the esophagus (gastroesophageal reflux).
Too much insulin may cause:
Low blood sugar. This can cause blurred vision, headache, and feeling lightheaded, tired, weak, shaky, nervous, irritable, sweaty, confused, or hungry.
Too much glucagon may cause:
Skin rash on the face, stomach, or legs.
High blood sugar. This can cause headaches, frequent urination, dry skin and mouth, or feeling hungry, thirsty, tired, or weak.
Blood clots. Blood clots in the lung can cause shortness of breath, cough, or pain in the chest. Blood clots in the arm or leg can cause pain, swelling, warmth, or redness of the arm or leg.
Weight loss for no known reason.
Sore tongue or sores at the corners of the mouth.
Too much vasoactive intestinal peptide (VIP) may cause:
Very large amounts of watery diarrhea.
Dehydration. This can cause feeling thirsty, making less urine, dry skin and mouth, headaches, dizziness, or feeling tired.
Low potassium level in the blood. This can cause muscle weakness, aching, or cramps, numbness and tingling, frequent urination, fast heartbeat, and feeling confused or thirsty.
Cramps or pain in the abdomen.
Weight loss for no known reason.
Too much somatostatin may cause:
High blood sugar. This can cause headaches, frequent urination, dry skin and mouth, or feeling hungry, thirsty, tired, or weak.
Steatorrhea (very foul-smelling stool that floats).
Yellowing of the skin and whites of the eyes.
Weight loss for no known reason.
Too much pancreatic polypeptide may cause:
an enlarged liver.
Clearly the presenting symptoms will give doctors a clue to the oversecreting hormone (see list above). Excessive secretions or high levels of hormones and other substances can be measured in a number of ways. For example:
Well known tests for the most common types of NET include 5-Hydroxyindoleacetic Acid (5-HIAA) 24 hour urine test which is also measured by a blood draw. Note: -tumor markers can be measured simultaneously e.g. Chromogranin A (CgA) blood test and/or Pancreastatin as there can very often be a correlation between tumour mass and tumour secreting activity. CgA / Pancreastatin is a blood test which measures a protein found in many NET tumour cells. These marker tests are normally associated with tumour mass rather than tumour functionality.
By measuring the level of 5-HIAA in the urine or blood, healthcare providers can calculate the amount of serotonin in the body (5-HIAA is a by-product of serotonin). 5-HIAA test is the most common biochemical test for carcinoid syndrome or the degree of how ‘functional’ tumours are. If you’ve understood the text above, you can now see why there are dietary and drug restrictions in place prior to the test.
Pancreatic Hormone testing. There are other tests for other hormones and there is a common test which measured the main hormones seen in NETs. It may be called different things in different countries, but in UK, it’s known as a ‘Fasting Gut Hormone Profile‘.
Scratching the surface here so for a comprehensive list of marker tests for NETs, have aread here.
Treatment for Over-secreting Hormones
Of course, reducing tumour bulk through surgery and other treatment modalities, should technically reduce over-secretion (I suspect that doesn’t work for all). Other treatments may have the dual effect of reducing tumour burden and the effects of hormone oversecretions.
One of the key treatment breakthroughs for many NET cancer patients, is the use of ‘Somatostatin Analogues’ mainly branded as Octreotide (Sandostatin) or Lanreotide (Somatuline). People tend to associate these drugs with serotonin related secretions and tumours but they are in actual fact useful for many others including the pancreatic NETs listed above. Patients will normally be prescribed these drugs if they are displaying these symptoms but some people may be more avid to the drug than others and this may influence future use and dosages. This is another complex area but I’ll try to describe the importance here in basic terms. Somatostatin is a naturally occurring protein in the human body. It is an inhibitor of various hormones secreted from the endocrine system (some of which were listed above) and it binds with high affinity to the five somatostatin receptors found on secretory endocrine cells. NETs have membranes covered with receptors for somatostatin. However, the naturally occurring Somatostatin has limited clinical use due to its short half-life (<3 min). Therefore, specific somatostatin analogues (synthetic versions) have been developed that bind to tumours and block hormone release. Thus why Octreotide and Lanreotide do a good job of slowing down hormone production, including many of the gut hormones controlling emptying of the stomach and bowel. It also slows down the release of hormones made by the pancreas, including insulin and digestive enzymes – so there can be side effects including fat malabsorption.
The recent introduction of Telotristat Ethyl(XERMELO) is interesting as that inhibits a precursor to serotonin and reduces diarrhea in those patients where it is not adequately controlled by somatostatin analogues.
Other than the effects of curative or cytoreductive surgery, some NETs may have very specialist drugs for inhibiting the less common hormone types. This is not an exhaustive list.
Worth also noting that oversecreting hormones can contribute to a phenomenon known as Carcinoid Crisis – read more here. For catacholamine secreting tumors (Pheochromocytoma/Paraganglioma), this may be known as Intraoperative Hypertensive Crisis
Sorry about the long article – it’s complex and you should always consult your specialist about issues involving hormones, testing for hormones and treating any low or high scores.