Ronny Allan’s ‘PoNETry’ © – An Ode to Invisible Illness

Ronny Allan’s ‘PoNETry’ © series can be shared with poetry credit to:

ronnyallan.com and/or NET Cancer Blog

 

Thanks for reading

Ronny

I’m also active on Facebook.  Like my page for even more news.  I’m also building up this site here: Ronny Allan

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Remember ….. in the war on Neuroendocrine Cancer, let’s not forget to win the battle for better quality of life!

Diagnosed with Neuroendocrine Cancer? – 10 questions to ask your doctor (and where to find a NET Specialist Worldwide)


find net specilaist and 10 qeusitons

On the day I was diagnosed, I hadn’t really thought about questions, the only one I actually remember asking was “how long do I have left to live” (I watch too many movies!). On the day of diagnosis and a period beyond, people tend to feel emotions of shock, denial, anger and sadness, before going on to accept their situation. Yes, I ‘googled‘ but not a great deal really – although some things I found did frighten me. I wish I had found this article way back then.

As things progressed in the weeks after ‘D-Day’, I started to work out the sort of things to ask but even then it was limited. I had been referred to an experienced NET team so I felt confident they would do whatever needed doing. In hindsight, I can now think of a quite a few questions I should have asked. That said, I suspect my team probably gave me the answers without having been asked the questions!

My blogging efforts have turned into a ‘Community’ of sorts. Consequently, I’m contacted daily from people finding me on the web. Many of these people are at the pre-diagnosis or initial phase. Many are undiagnosed. Most are looking for information and some sound like they are already at the ‘acceptance stage’; some are frightened about the future, some are angry because they think they are not being told important information and some also feel they have been messed about or ‘fobbed off’ by their doctors. Of course I’m happy to help but only after reminding them that I’m just a wee Scottish guy with the same disease!

I have to say that some people arrive on my site without a diagnosis but often seem to be very well prepared – the power of the internet I suspect. The questions I mostly get involve finding experts and then what questions to ask them.

Finding experts

As an extra bonus to this post, I offer you a starting point for the best places I know for finding NET expertise:

Europe – here at ENETS: European NET Centres of Excellence

UK – here at UKINETS: UK NET Centres

USA:

  • One US center is now the first to achieve a European NETs Center of Excellence accreditation – read more hear about University of Iowa Holden Comprehensive Cancer Centerclick here
    NANETS have listed “NET Centers” here – NANETS NET Centers and Clinics
  • The NET Research Foundation as they also have a ‘Doctor Database’ section which differs slightly from CCF below.
  • Here at Carcinoid Cancer Foundation – Find a Doctor

Australia – here: Australian NET Doctors

New Zealand – Dr Ben Lawrence, based in Aukland.

Canada (from patient knowledge):

  • Dr. Simron Singh at Sunnybrook in Toronto
  • Dr. Shereen Ezzat at Princess Margaret in Toronto (PMH)
  • Dr. McEwan, The Cross Clinic, Alberta?
  • Dr Kavan at Montreal Jewish General Hospital (Oncology)
  • Dr Buteau / Beauregard at Quebec Hotel Dieu (Radiation Oncology (PRRT, Ga68)
  • Dr Rivera at Montreal General Hospital (Endocrinology)
  • Dr Metrakos at the Montreal Royal Victoria Hospital (Surgeon) sees a lot of NET patients
  • On the French side Dr Andre Roy at the CHUM in Montreal (surgeon) also sees a lot of NET patients
  • Dr. Jamil Asselah also treats net patients. He is an oncologist….Quebec
  • Michael Sawyer at Cross Clinic in Alberta Edmonton.
  • Drs. Parkins, Card, and Paseka at the Tom Baker CC in Calgary.
  • London Ontario: Dr. David Laidley, Dr. Robert Reid in the Neuroendocrine Clinic at London Regional Cancer Program and Dr. Daryl Gray, Surgeon.

Russia – Clinical Oncology Research Institute, N. N. Blokhin RCRC RAMS, Address: 24, Kashirskoye sh., Moscow, 115478, RF. NET specialist Alla Markovich

In my Group – ask other patients: Click here to join.

AskDoctor_0

Neuroendocrine Cancer – 10 questions to ask your specialist

Many people ask me what sort of questions to ask and because NETs is such a diverse bunch of diseases, that leads to me ask them a series of questions to ascertain what they might consider asking. I’m not surprised to find some are unable to answer my questions and so those then become some of their questions to ask!

Also, questions don’t end at the diagnosis phase, they continue and in fact, some of the answers to the questions below, may bring up new questions in your mind. Some of these questions can be asked time and time again in the event of issues downstream.

If you’re currently confused about the essential facts of your condition, you’re not alone. In a recent study, almost half of cancer patients did not know basic stuff such as grade and stage of cancer, and after their initial treatment, whether they were free of disease or in remission.

Pre-question Check

For those entering or are recently just beyond the diagnostic phase, you may find certain questions cannot yet be answered without further test results etc. However, if the answer is not yet known for whatever reason, at least you have it on your list for follow up appointments. Consequently, I’ve constructed this list of questions that should function as a generic set. There may also be ‘specific to country’ questions such as insurance cover in addition to this suggested list. Of course, some of you may not want the answer to so certain questions. That’s perfectly understandable, so don’t ask!

1. Where is my primary tumour and what type of NET is it?

This is a fundamental question and it’s likely many will already have some inkling about location and perhaps a type. The difference between NETs and other types of cancer is the primary can be found wherever there are Neuroendocrine cells rather than a specific part of the anatomy in terms of naming the type of cancer, i.e. a NET of the pancreas is not Pancreatic Cancer.

The type of NET is key as it will drive a lot of other stuff including treatment. Location and type of NET are not always aligned, for example, you may have a NET in your Pancreas but there are several types of Pancreatic NET (or pNET) and these may depend on identification of a particular hormone (see syndrome below). Many NETs are non-functional (there is no oversecreting hormone).

For some the primary will not yet be found (i.e. cancer of unknown primary or CUP). There may also be multiple primaries.

2. What is the grade and differentiation of my tumour(s)?

Another fundamental question as this defines the aggressiveness of the disease and is absolutely key in determining overall treatment plans. Treatment plans for poorly differentiated can be very different from well differentiated. Read more here – Grading and here – Benign or Malignant

3. What is the stage of my disease?

Fundamental to understanding the nature of your disease. Stage confirms the extent of your disease, i.e. how far has it spread. Again this will drive treatment plans and long-term outlooks. Scans are really important in determining the Stage of your cancer – check out my scans post here. Read more here on Staging

4. Do I have a NET Syndrome?

Many NET patients will have been experiencing symptoms prior to diagnosis, perhaps for some time. It’s possible these symptoms form part of what is known as a ‘Syndrome’ and there are several associated with NETs. Syndromes are mostly caused by the effects of over-secretion of hormones from the tumours, a hallmark of Neuroendocrine disease. Carcinoid Syndrome is the most common but there are many more depending on the primary location. Read more here – NET Syndromes.

5. What is my treatment plan, and what are the factors that will influence my eventual treatment? When will I start treatment

This is a very complex area and will depend on many factors. Thus why your specialist may not have the answers to hand. Decisions on treatment are normally made by some form of Multi-disciplinary Team (MDT).  Many people diagnosed with cancer expect to be whisked away to an operating theatre or chemotherapy treatment. However, for many this is not what actually happens. Depending on what testing has been done up to the actual diagnosis, it’s possible that even more testing needs to be done. Additionally, for those with an accompanying syndrome, this will most likely need to be brought until control before certain treatments can be administered; and even then, there may be checks to make sure the treatment will be suitable. Sometimes it’s a case of ‘Hurry up and wait’. My first treatment was 6 weeks after diagnosis and that was designed to control my syndrome ready for surgery which was undertaken 14 weeks after diagnosis. It’s also possible you will be placed on a ‘watch and wait’ regime, at least to begin with.

6. Can you comment on the potential for my type of NET to be related to any familial or genetic aspects of cancer?

A small percentage of NETs are hereditary/genetic in nature.  This is mostly associated with those who have Multiple Endocrine Neoplasms (MEN) syndromes  and a few other less common types of NET including Pheochomocytoma / Paraganglioma(Pheo/Para) and Medullary Thyroid Carcinoma (MTC) (the familial version of MTC is often referred to as FMTC). However, please note this does not mean that all those diagnosed with pancreatic, parathyroid, pituitary, Pheo/Para and MTC tumours, will have any hereditary or genetic conditions, many will simply be sporadic tumors.

7. Will you be able to get rid of all my disease?

This is a really difficult question for any specialist, even a Neuroendocrine expert. All published articles on NETs will say they are a heterogeneous collection of diseases (i.e. consisting of dissimilar entities) which makes this question (and others) difficult. I have read articles written by the world’s foremost NET experts and they all have the word ‘curative’ mentioned in various places. So I guess in particular scenarios with certain NETs, and if the disease is caught early enough, that possibility exists. However, for many, the disease could be incurable, particularly where there is distant metastasis. But, the disease has many treatment options for most types and for many it is possible to live as if it were a chronic condition. I call it ‘incurable but treatable’. Read more here – Incurable vs Terminal

8. What Surveillance will I be placed under?

Again, this is very individual in NETs and is mainly dependent on type of NET, grade and stage and how the patients reacts to treatment. This may not be known until you have undergone your initial treatment. For example, surveillance scans can be any period from 3 months to 3 years depending on tumour type(location) and stage/grade. Marker testing tends to average around 6 monthly but could be more or less frequently depending on what’s going on. Read more here – click here

9. Will I receive support and specialist advice after my treatment?

Let’s not be afraid of the word ‘Palliative’, it does not always mean ‘end of life’ care. Another example is nutrition. Many people with NETs, the condition in combination with the side effects of treatment may necessitate an alteration of diet and this is a very individual area. I would also emphasise that dietitians not well versed in NETs might not offer the optimum advice. Read more – My Nutrition Series.

10. How will treatment affect my daily life?

This is a question that many people miss but it’s becoming more important as we all live longer with cancer Again, this may not be possible to answer immediately but perhaps this question could be reserved once you know which treatment(s) you will be receiving. All treatment comes with side effects and can last for some time or even present with late effects after some years. The ‘consequences’ of cancer treatment need to be factored in earlier so that the necessary knowledge and support can be put in place. See also Unmet Needs for NET Patients

I suspect others will have suggestions for this list so feel free to submit these to me. I quite often refresh my posts over time.

NET Syndromes – chicken or egg?


We’ve all heard the age-old question about the chicken and the egg?  Scientists claimed to have ‘cracked’ the riddle of whether the chicken or the egg came first. The answer, they say, is the chicken. Researchers found that the formation of egg shells relies on a protein found only in a chicken’s ovaries. Therefore, an egg can exist only if it has been inside a chicken. There you have it!

On a similar subject, I’m often confused when someone says they have been diagnosed with ‘Carcinoid Syndrome’ and not one of associated ‘Neuroendocrine Tumours’.  So which comes first?  I guess it’s the way you look at it. In terms of presentation, the syndrome might look like it comes first, particularly in cases of metastatic/advanced disease or other complex scenarios.  Alternatively, a tumour may be found in an asymptomatic patient, quite often incidentally.  However, on the basis that the widely accepted definition of Neuroendocrine Tumours would indicate that a syndrome is secondary to tumour growth, then the tumour must be the chicken.

I sometimes wonder what patients are told by their physicians….. or perhaps by their insurance companies (more on the latter below). That said, I did see some anecdotal evidence about one person who was diagnosed with Carcinoid Syndrome despite the lack of any evidence of tumours or their markers. This might just be a case of providing a clinical diagnosis in order to justify somatostatin analogue treatment but it does seem unusual given that scientifically speaking, Carcinoid Syndrome can only be caused by a particular type of NET.

I have a little bit of experience with this confusion and it still annoys me today.  Shortly after my diagnosis, I had to fill out an online form for my health insurance.  The drop down menu did not have an entry for Neuroendocrine ‘anything’ but I spotted Carcinoid only to find it was actually Carcinoid Syndrome.  By this stage I had passed the first level of NET knowledge and was therefore suspicious of the insurance company list.  I called them and they said it was a recognised condition and I should not worry.  Whilst that statement might be correct, I did tell them it was not a cancer per se but an accompanying syndrome caused by the cancer. I added that I was concerned about my eligibility for cancer cover treatment and didn’t want to put an incorrect statement on the online form. However, they persisted and assured me it would be fine on that selection.  On the basis it was really the only option I could select, I selected and submitted.  I did get my cover sorted.  However, it’s now clear to me that their database was totally out of date.  A similar thing happened when I was prescribed Octreotide and then Lanreotide, the only ‘treatment type’ they could find on their database was ‘chemotherapy‘ – again their system was out of date.  I’m told by someone in the know, that individual insurance companies are not responsible for this list, they all get it from a central place  – I’d love to pay that central place a visit!

I quickly thought about all the other NET Syndromes for their ‘chicken and egg’ status! Pancreatic NET (pNET) Syndromes must all be ‘chicken’ given the tumour definition and the secretion of the offending hormones that cause these other syndromes e.g. Insulin, Gastrin, Glucagon, Pancreatic Polypeptide (PP), Vasoactive Intestinal Peptide (VIP) and Somatostatin, etc.

All of that said, the exception might be hereditary syndromes e.g. MEN (yes it is a syndrome, not a tumor type).  MEN syndromes are genetic conditions. This means that the cancer risk and other features of MEN can be passed from generation to generation in a family. A mutation (alteration) in the various MEN genes gives a person an increased risk of developing endocrine/neuroendocrine tumors and other symptoms of MEN. It’s also possible that the tumors will be discovered first.  It’s complex as you will see in my article entitled “Genetics and Neuroendocrine Tumors”.

 

Thanks for reading

Ronny

I’m also active on Facebook. Like my page for even more news. I’m also building up this site here: Ronny Allan

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Remember ….. in the war on Neuroendocrine Cancer, let’s not forget to win the battle for better quality of life!

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Neuroendocrine Cancer – If you can see it, you can detect it!

octreo-vs-g68
Octreoscan vs Ga68 PET

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:

Conventional Imaging

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.

Ultrasound (US)

Liver_Metastases_Ultrasound

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)

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.

Somatostatin receptor-based imaging techniques

owl ga68
Graphic courtesy of Advanced Accelerator Applications

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.

Read more about Ga68 PET scans by clicking here

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 PET Imaging in Neuroendocrine Tumors” which gives guidance on it’s use – issued by the Society of Nuclear Medicine and Molecular Imaging (SNMMI).

Other PET Scans

18FDG PET

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.

18F-FDOPA PET

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.

I-MIBG

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).

Miscellaneous Scans

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 Sestsestamibiamibi 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.

Skeletal Scintigraphy (bone scan)

Quite often, bone metastases in NETs will be found via conventional imaging or special to NET nuclear scans such as Ga68 PET or MIBG.  However, a bone scan can often find them or confirm findings of scans looking for NETs.

Skeletal scintigraphy is a special type of nuclear medicine procedure that uses small amounts of radioactive material to diagnose and assess the severity of a variety of bone diseases and conditions, including fractures, infection, and cancer.

Nuclear medicine imaging procedures are non-invasive and — with the exception of intravenous injections — usually painless medical tests that help physicians diagnose and evaluate medical conditions. These imaging scans use radioactive materials called radiopharmaceuticals or radiotracers. Radioactive energy emitted from the radiotracer is detected by a special camera or imaging device that produces pictures of the bones called scintigrams. Abnormalities are indicated by areas of abnormal bone that take up more or less of the radiopharmaceutical which appear brighter or darker than normal bone on the scintigram.

Because nuclear medicine procedures are able to image the functions of the body at the molecular level, they offer the potential to identify disease in its earliest stages as well as a patient’s response to therapeutic interventions. In fact, a bone scan can often find bone abnormalities much earlier than a regular x-ray exam.

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

explorer pet scan

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:

Summary

If you can see it, you can detect it.

Sources:

1. Imaging in neuroendocrine tumors: an update for the clinician, Maxwell, Howe,

2. Appropriate use Criteria for Somatostatin Receptor PET Imaging in Neuroendocrine Tumors,

3. Radiology for Patients,

4.  Useful video from NET Research Foundation about which scans to use for which job.  CLICK HERE to watch.

5.  Useful video summary from the NET Patient Foundation describing the different scans for NET Cancer and what to expect.  Worth a look.  CLICK HERE for the scan video

Sooner we can ALL get access to the latest radionuclide scans the better – this is currently an unmet need in many countries.

If you are any doubt about which type of scan is best for you and their availability, please consult your specialist.

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!

CLICK HERE for the scan video

Thanks for reading

Ronny

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Neuroendocrine Cancer – tumour markers and hormone levels


blood

I think most people have had a form of medical testing at some point in their life, i.e. the sampling and testing of blood, urine, saliva, stool or body tissue. In a nutshell, the medical staff are just measuring the content of a ‘substance’ and then taking a view whether this is normal or not based on pre-determined ranges. These tests are normally done as a physician’s reaction to symptom presentation or maintenance/surveillance of an existing diagnosed condition. Sometimes, abnormal results will lead to more specialist tests.

In cancer, these tests are frequently called ‘markers’. Most tumour markers are made by normal cells as well as by cancer cells; however, they are produced at much higher levels in cancerous conditions. These substances can be found in the blood, urine, stool, tumour tissue, or other tissues or bodily fluids of some patients with cancer. Most tumour markers are proteins. However, more recently, patterns of gene expression and changes to DNA have also begun to be used as tumour markers.  Many different tumour markers have been characterized and are in clinical use. Some are associated with only one type of cancer, whereas others are associated with two or more cancer types. No “universal” tumour marker that can detect any type of cancer has been found.

markers

There are some limitations to the use of tumor markers. Sometimes, noncancerous conditions can cause the levels of certain tumor markers to increase. In addition, not everyone with a particular type of cancer will have a higher level of a tumour marker associated with that cancer. Moreover, tumour markers have not been identified for every type of cancer. Tumour markers are not foolproof and other tests and checks are usually needed to learn more about a possible cancer or recurrence.

I’d also like to talk about a group of associated tests, in particular, hormone levels as these tests are really important to help determine the type of Neuroendocrine Tumour.  NETs will sometimes oversecrete hormones and this can give clues to the type.  The constraints mentioned above apply to hormone levels and other tests to a certain extent.

What this article will not cover

Routine Testing – the post will not cover routine blood tests (i.e. complete blood count etc).  Although they may point to a problem, these tests do not necessarily indicate a particular type of NET without other supporting evidence.

Biopsy Testing – Technically, the Immunohistochemical ‘stains’ used in biopsy testing are tumour markers but I’ll not be discussing that today. I did cover the output of biopsies in my blog on NETs – Stages and Grades.

Genetic Testing.  This is very specialised but you may find my Genetics and NETs article is of interest.

Sequencing of marker testing – diagnosis

The sequencing of marker testing may have been different for many patients.  In my own experience, I had a biopsy and then the biochemical checks were carried out. So regardless of the results of my marker tests, I was to be diagnosed with NETs. Those with lengthy and difficult diagnostic phases will perhaps have had a different sequence with the biochemical markers providing evidence for further tests to formally diagnose.  Markers alone will normally not be enough for a diagnosis but they do, however, feed into the treatment plan and provide a baseline at diagnosis and for tracking going forward.

Interpreting test results – International/National/Regional differences

The use of markers tends to be different on an international basis, e.g. specific marker tests can be developed in-country by independent labs. Testing can also vary in the same country as in-country labs use different commercially available ‘testing kits’. Not all tests are available in all countries.

Reference ranges can be dependent on many factors, including patient age, gender, sample population, and test method, and numeric test results can have different meanings in different laboratories. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the tests to obtain the reference range if you do not have the lab report. Moreover, the ‘normal’ test range can vary from hospital to hospital, even within the same tests. I suspect clinical staff have their own versions of risk thresholds when dealing with test results. Even when results are just above or below, individual physicians can take their own view in a subjective manner. Testing is best done at the same lab each time if possible.

There’s a great website called LabTestsOnline which can describe each test. It’s peer-reviewed, non-commercial and patient-focused but just please note you should always refer to your own lab ‘normal ranges’ which will be printed on your test results.  For these reasons, you will not find reference ranges for the majority of tests described on this web site.  The link above will take you to the list of ‘country’ affiliated versions with specific information on a country basis.

Here’s some tips I always give people:

1 – Always try to get your own copy of results (preferably on paper) and track them yourself (I use a spreadsheet).

2 – When comparing results inside patient forums, always add the range and if possible, the unit of measurement (i.e. g/L, mmol/L, umol/L etc etc).  Failure to do this can at best confuse, and at worst frighten patients.  Compare apples with apples not with pears! (this is why it’s important to know the unit of measure and the reference range in addition to the figure).

3 – Don’t get too excited about rises if the test is still inside the normal range – normal is normal!

4 – Don’t get too excited about rises taking you just outside of normal range – your doctors are looking for bigger spikes.

5. Don’t get too excited about a single test result, your doctors are looking for trends, a single test result is not much to go on.

NET Markers

Although some routine blood markers (complete blood count etc) are useful in NETs, it’s pretty much impossible to cover these in any general detail.  I’m going to focus on tumor and hormone associated markers

There are many markers involved with NETs. Some do different jobs and some are just variants measuring the same thing (more or less efficiently). You may also see something called ‘gold standard’ in reference to NET Tumour markers. Although thinking is changing (more on this below) and can vary from country to country, it is generally accepted that Chromogranin A and 5HIAA are the gold standard markers for tumour bulk and tumour functionality respectively.  These gold standard tests may not be applicable to every type of NET, particularly 5HIAA. I’m also aware that US doctors are reducing the dependency on CgA and using Pancreastatin instead (although many are measuring both).

NETs are known to be heterogeneous in nature (i.e. consisting of or composed of dissimilar elements; not having a uniform quality throughout).  Whilst some markers can be used widely, it follows that there are many very specialist marker tests for individual types of NET.  I think this applies to 3 broad categories of NETs: Tumours known to potentially oversecrete Serotonin and and perhaps others (mainly midgut), Pancreatic NETs (or pNETs) secreting various hormones by type; and other less common types and/or syndromes which might be considered by some to be even more complex than the former two and in some cases there are big overlaps.

Another interesting thing about NET markers is that an undiagnosed patient may undergo several specialist tests to eliminate the many possibilities that are being presented as vague and common symptoms.  Sometimes this is necessary to eliminate or ‘home in’ on a tumour type or syndrome/hormone involved (it’s that jigsaw thing again!).

Markers too can be divided into broad categories, those measuring how much tumour is in your body and its growth potential and those measuring how functional (or not) those tumours are.  The latter can probably be expanded to measure/assess excess hormone secretion and syndromes.

The Anatomy

Certain tests can be anatomy related so to add context and to prevent big repetitive lists when using the terms ‘foregut’, ‘midgut’ and ‘hindgut’, you may find this graphic useful.

foregut midgut hindgut

Markers for measuring Tumour bulk or load/growth prediction

Chromogranin (plasma/blood test)

cgaChromogranin is an acidic protein released along with catecholamines from chromaffin cells and nerve terminals. This statement alone might explain why it is a good marker to use with NETs.  Depending on the test kit being used, you may see test results for Chromogranin A (CgA) and Chromogranin B (CgB) – the inclusion of CgB tends to be confined to Europe. There is also mention of Chromogranin C (CgC) in places but I’ve never heard of this being used in conjunction with NETs.

One of the disadvantages of CgA is that the results can be skewed by those taking Proton Pump Inhibitors (PPIs).  Many NET patients are taking PPIs to treat GERD (….and Zollinger-Ellison Syndrome). In the long-term, this has the result of increasing gastrin levels which can lead to an increase of CgA in the blood including for some months after discontinuing.  Opinions differ but many texts I found did suggest stopping PPIs for 2 weeks before the CgA blood test.  CgB is said not be as influenced by the use of PPI as CgA. In addition to the issue with PPIs, CgA levels may also be elevated in other illnesses including severe hypertension and renal insufficiency. CgB is also said to be more sensitive to Pheochromocytoma.

Elevated CgA is a constant and somewhat excitable discussion point on patient forums and not just because of the lack of unit of measurement use I discussed above. Some people get quite excited about a single test result.  I refer to Dr Woltering et al (ISI Book) where it clearly states that changes in CgA levels of more than 25% over baseline are considered significant and a trend in serial CgA levels over time has been proven to be a useful predictor of tumour growth (i.e. a single test result with an insignificant rise may not be important on its own).  Dr Woltering also gives good advice on marker tests when he says “normal is normal” (i.e. an increased result which is still in range is normal).

Here is a nice graphic explaining what else could be the cause of elevated CgA:

causes-of-cga-elevated

CgA appears to be a widely used tumour marker and is effective in most NETs (foregut, midgut and hindgut). It is also sensitive to Pheochromocytoma, particularly when correlated with a 131I-MIBG scan. Interestingly Chromogranin can also be used in the immunohistochemical staining of NET biopsy samples (along with other methods).

As for my own experience, my CgA was only elevated at diagnosis, remained elevated after intestinal surgery but returned to normal after liver surgery (indicating the effect of liver tumour bulk on results).  It also spiked out of range when some growth in a distant left axillary node was reported in Jan 2012.  Following a lymphadenectomy, it returned to normal again and has remained in range to this day.  It has been a good predictor of tumour bulk for me and I’m currently tested every 6 months.

Pancreastatin

In effect, this marker does the same job as CgA.  Interestingly, Pancreastatin is actually a fragment of the CgA molecule. There have been many studies (mainly in the US) indicating this is a more efficient marker than CgA, and not only because it is not influenced by the use of PPI.  It has also been suggested that it’s more sensitive than CgA and therefore capable of detecting early increases in tumour burden. It has also been suggested it can be an indication of tumour ‘activity’ (whatever that means). It is widely used in the US and some physicians will use it in preference to CgA (…..although from what I read, CgA also seems to be tested alongside).  I’m starting to see this mentioned in the UK.

Neurokinin A (NKA)

This is not a well publicised test. However, it is something used in USA but I’d like to hear from others to validate its use elsewhere.  In a nutshell, this test, which only applies to well differentiated midgut NETs, appears to have some prognostic indication.  I discovered this test in the ISI NET Guidance and it’s backed up by a study authored by names such as Woltering, O’Dorisio, Vinik, et al.  This is not a one-off test but one designed to be taken serially, i.e. a number of consecutive tests.  These authors believe that NKA can also aid in the early identification of patients with more aggressive tumors, allowing for better clinical management of these patients.  NKA is sometimes called Substance K.

Neuron-Specific Enolase (NSE)

In patients with suspected NET who have no clear elevations in the primary tumor markers used to diagnose these conditions, an elevated serum NSE level supports the clinical suspicion.

Markers for measuring Tumour functionality/hormone/peptide levels

So far, I’ve covered basic tumor markers which have a tumor bulk and/or prognostic indication.  This section is a slightly more complex area and many more tests are involved. There’s often a correlation between CgA/Pancreastatin and these type of markers in many patients i.e. a serial high level of CgA might indicate a high level of tumour bulk and therefore increased production of a hormone in patients with a syndrome or oversecreting tumor. However, it frequently does not work out like that, particularly when dealing with non-functioning tumours.

The type of marker for this element of NET diagnosis and surveillance will vary depending on the type of NET and its location (to a certain extent).  Like tumour bulk/growth, there might be different options or test variants on an international basis. There are too many to list here, so I’ll only cover the most common.

Serotonin Secreting Tumors

There are a few markers in use for measuring the functionality of this grouping of tumours. This tumour group has a tendency to secrete excess amounts of the hormone Serotonin although it differs depending on the area of the primary. For example, hindgut tumours tend to secret lower levels than foregut and midgut and therefore this test may present within range.  Please also note there may be other hormones of note involved. The antiquated and misleading term ‘Carcinoid’ is sometimes used as a descriptor for these tumours and more and more NET scientific organisations and specialists are now avoiding use of this term.

lug-the-jug
Lug the Jug

5HIAA.  5HIAA is a metabolite of Serotonin thus why it’s a useful thing to measure to assess functionality in this grouping of tumours. 5HIAA is actually the ‘gold standard’ test for functioning serotonin secreting tumours. It’s a key measure of the effects of carcinoid syndrome and the risk of succumbing to carcinoid heart disease.  However, there are two methods of testing:  Urine and Plasma. The latter is mainly used in USA but other countries are now looking at implementing the plasma version (in fact I’m now tested in both at my local hospital in UK).  The rather obvious key difference between the two is practicality. With the 24 hour urine, there are two key issues: 1.  The logistics (i.e. lug the jug).  2.  Fasting for up to 3 days prior to the test (4 if you count the day of the test). There are numerous variations on the fasting theme but most labs tend to say not to eat at least the following foods that contain high levels of serotonin producing amines: avocados, bananas, chocolate, kiwi fruit, pineapple, plums, tomatoes, and walnuts.  Some lists contain additional items. With the plasma version, the fasting period is reduced to 8 hours. There are also medicinal limitations including drugs that can also alter 5-HIAA urine values, such as acetanilide, phenacetin, glyceryl guaiacolate (found in many cough syrups), methocarbamol, and reserpine. Drugs that can decrease urinary 5-HIAA levels include heparin, isoniazid, levodopa, monoamine oxidase inhibitors, methenamine, methyldopa, phenothiazines, and tricyclic antidepressants. Patients should talk to their doctor before decreasing or discontinuing any medications.

As for my own experience, my 5HIAA (urine) was elevated at diagnosis only returning to normal after removal of my primary and commencement of Lanreotide. It has been a good measure of tumour functionality for me and I’m currently tested every 6 months.

Other tests for the tumour subgroup include but not limited to:

Serum Serotonin (5-HydroxyTryptamine; 5-HT).  Firstly let’s deconflict between 5HIAA above and the serotonin (5-HT) blood test.  5HIAA is a metabolite of serotonin but the serotonin test is a measure of pure serotonin in the blood.  Morning specimens are preferred and this is a fasting test (10-12 hours).  There is always debate on forums about Serum Serotonin results.  I have Dr Liu on record as saying “a high serotonin level measured in the blood in isolation really isn’t that dangerous. It’s the 5HIAA (a breakdown product of serotonin, which is easily measured in the blood and urine) that is considered to be more indicative of persistent elevated hormone. It’s this test that is most closely related to the carcinoid heart disease”.

Substance P.   A substance associated with foregut and midgut tumours.  It is a vasoactive protein that can cause wheezing, diarrhea, tachycardia, flushing

Histamines – Usually associated with foregut tumors. Appears to be involved in patchy rashes and flushing.  The advice in the ISI NET book is no anti-histamine medication to be taken for 48 hours prior to blood draw.

Gastric NETs (Stomach)

Testing will be different depending on the Type:

  • Type 1 – Typical Low Grade, tends to be caused by atrophic gastritis.
  • Type 2 – Atypical Intermediate Grade and tends to be caused by gastrin secreting tumours.  Type 2 normally needs a check for MEN1/Zollinger-Ellison Syndrome.
  • Type 3 – Tend to be larger and more aggressive tumours.

The key makers are CgA and Gastrin although Gastrin may not be elevated in Type 3. Gastrin ph is useful to differentiate between Type 1 and Type 2.  5HIAA can be considered but Carcinoid Syndrome is rare in Gastric NETs.

NETs of the Pancreas (pNETs)

pancreatic-cells
There are many different types of cells in the pancreas

pNETs can be very difficult to diagnose and not only because they share some presentational similarities to their exocrine counterparts.  Some pNETs actually comprise tumours arising in the upper part of the duodenum (small intestine) close to the Pancreas. Moreover, more than half of pNETs are non-functional which increases the difficulty in suspecting and then finding the tumours.  However, where there is clinical presentation or suspicion, these symptoms can lead to the appropriate testing to support the output of scans. The fasting gut profile mentioned above can be useful in identifying the offending hormones when the type of NET is not yet known.

Gut Hormones (Glucagon, Gastrin, VIP, Somatostatin, Pancreatic Polypeptide)

A gut hormone screen is used for the diagnosis of a variety of endocrine tumours of the pancreas area. Analysis includes gastrin, VIP, somatostatin, pancreatic polypeptide, and glucagon, but there may be others depending on processes used by your ordering specialist or hospital.

Notes:

1. You may see this referred to as a ‘Fasting Gut Profile’ or a ‘Fasting Gut Hormone Profile’.

2.  The individual hormones measured seem to differ between hospital labs.

3.  The fasting conditions also vary between hospitals and labs but all agree the conditions are critical to the most accurate results. Always ask for instructions if you’re offered this test.

The gastrin test is usually requested to help detect high levels of gastrin and stomach acid. It is used to help diagnose gastrin-producing tumours called gastrinomas, Zollinger-Ellison (ZE) syndrome, and hyperplasia of G-cells, specialised cells in the stomach that produce gastrin. It may be measured to screen for the presence of multiple endocrine neoplasia type I (MEN) It may be used if a person has abdominal pain, diarrhoea, and recurrent peptic ulcers. A gastrin test may also be requested to look for recurrence of disease following surgical removal of a gastrinoma.

Vasoactive intestinal peptide (VIP) measurement is required for diagnosis of pancreatic tumour or a ganglioneuroma which secretes VIP. Administration of VIP to animals causes hyperglycaemia, inhibition of gastric acid, secretion of pancreatic bicarbonate and of small intestinal juice, and a lowering of systemic blood pressure with skin flush. These features are seen in patients with a tumour of this type which is secreting VIP.

Glucagon is measured for preoperative diagnosis of a glucagon-producing tumour of the pancreas in patients with diabetes and a characteristic skin rash (necrolytic migratory erythema).

Pancreatic polypeptide (PP) production is most commonly associated with tumours producing vasoactive intestinal polypeptide and with carcinoid syndrome and, less commonly, with insulinomas and gastrinomas.

When secreted by endocrine tumours, somatostatin appears to produce symptoms similar to those seen on pharmacological administration, i.e. steatorrhoea, diabetes mellitus and gall stones.

There are several types of pNETs, each with their own syndrome or hormone issue.  When they are suspected due to the presentational symptoms, the markers that could be used are listed below.  These types of tumours are complex and can be related to one or more syndromes.  A patient may be tested using multiple markers to include or exclude these.  Depending on other factors, some physicians may recommend additional marker testing in addition to the most common types below.

Insulinoma – Insulin, Proinsulin, C-peptide

Gastrinoma– Gastrin, Gastrin pH

Glucagonoma – Glucagon, Insulin, Pancreatic Polypeptide (PP), Adrenocorticotropic hormone (ACTH)

VIPoma – Vasoactive Intestinal Polypeptide (VIP), Electrolytes (due to profuse diarrhea)

Somatostatinoma – Somatostatin (plasma somatostatin like immunoreactivity)

PPoma – Pancreatic Polypeptide (PP)

Other NETs/Syndromes

Pheochromocytoma/Paraganglioma – Adrenaline-producing tumours. Plasma and urine catecholamines, plasma free total metanephrines, urine total metanephrines, vanillylmandelic acid (VMA)

Medullary Thyroid Cancer. Medullary thyroid cancer (MTC) starts as a growth of abnormal cancer cells within the thyroid – the parafollicular C cells. In the hereditary form of medullary thyroid cancer (~20% of cases, often called Familial MTC or FMTC), the growth of these cells is due to a mutation in the RET gene which was inherited. This mutated gene may first produce a premalignant condition called C cell hyperplasia. The parafollicular C cells of the thyroid begin to have unregulated growth. In the inherited forms of medullary thyroid cancer, the growing C cells may form a bump or nodule in any portion of the thyroid gland.  Unlike papillary and follicular thyroid cancers, which arise from thyroid hormone-producing cells, medullary thyroid cancer originates in the parafollicular cells (also called C cells) of the thyroid. These cancer cells make a different hormone called calcitonin, which has nothing to do with the control of metabolism in the way  thyroid hormone does.  The other test often seen in MTC is Carcinoembryonic Antigen (CEA). CEA is a protein that is usually found in the blood at a very low level but might rise in certain cancers, such as medullary thyroid cancer. There is no direct relationship between serum calcitonin levels and extent of medullary thyroid cancer.  However, trending serum calcitonin and CEA levels can be a useful tool for doctors to consider in determining the pace of change of a patient’s medullary cancer.

[please note there are extremely rare occurrences of elevated calcitonin from places outside the thyroid – read more here.

Parathyroid– Parathyroid hormone (PTH), Serum Calcium.  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 – see MEN below.

Pituitary/Cushings – Adrenocorticotropic hormone (ACTH), Cortisol.

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.

Adrenocorticotropic hormone (ACTH) 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. ACTH is secreted in several intermittent pulses during the day into the bloodstream and transported around the body. Like cortisol (see below), levels of ACTH 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 ACTH are mainly due to the increase in cortisol levels which result. Higher than normal levels of ACTH may be due to:

Cushing’s disease – this is the most common cause of increased ACTH. It is caused by a tumor in the pituitary gland (PitNET), which produces excess amounts of ACTH. (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.

Cortisol

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.

A tumour outside the pituitary gland, producing ACTH (also called ectopic ACTH). With NETs, this is normally a pNET, Lung/Bronchial NET or Pheochromocytoma.

Multiple Endocrine Neoplasia (MEN).  Please note MEN is a group of distinct syndrome not a tumor.  Complex area and tends to be multiple instances of some of the tumours above.  For a breakdown of MEN types and locations, check out my MEN blog ‘Running in the Family’

Carcinoid Heart Disease(CHD) (Hedinger syndrome)  I’m not really talking directly about a tumour here but thought it would be useful to include a blood test called NT-proBNP.  I’ve left a link to my CHD article in the paragraph heading for those who wish to learn more about CHD in general.  For those not offered an annual Echocardiogram or are ‘non-syndromic’ there is a screening test that can give an indication of any heart issue which might then need further checks.

The Future – Molecular Markers?

This is testing using DNA and genes.  Exciting but complex – check out this article which involved some NETs.

Tumour Markers and Hormone levels – complex subject!

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Running in the Family – Multiple Endocrine Neoplasia (MEN)


CancerDNAMarkers__0327

We all know that Neuroendocrine Tumours (NETs) and their syndromes are complex but there is even more complexity to be found in a group of related disorders known as Multiple Endocrine Neoplasia (MEN).  I recommend all NET patients should try to understand the basics of MEN and vice versa, particularly as both conditions seem to come with a plethora of endocrine related effects.

Overview

MEN patients will normally have a tumour in at least two endocrine glands – thus the terms ‘Multiple’ and ‘Endocrine’ (tumours can also develop in other organs and tissues).  Neoplasia is just another name for tumour and these can be non-cancerous (benign) or cancerous (malignant) with the potential to metastasize.

MEN syndromes can comprise varying combinations of tumours and many will be aware of the tumour risks from family knowledge.  So putting the heredity aspects to one side, it’s potentially an extremely challenging surveillance and subsequent diagnostic scenario if (and when) these risks are realised.  To add to the complexity, some of the associated tumours can be sporadic (non hereditary) classic Neuroendocrine Tumours in various locations.

MEN Types

MEN is actually an umbrella term for a number of types (syndromes) of the disease – MEN1, MEN2a and 2b (2b was formerly MEN3). There’s a new kid on the block called MEN4 which is extremely rare.

In the most basic of terms regarding the relationship with tumours:

MEN1 seems to be centred on tumours of the parathyroid glands, the pituitary gland, and the pancreas (the 3 P’s).

MEN2a mainly focuses on medullary thyroid carcinoma, pheochromocytoma, parathyroid hyperplasia or adenomas (causing hyperparathyroidism), and occasionally cutaneous lichen amyloidosis.

MEN2b  medullary thyroid carcinoma, pheochromocytoma, multiple mucosal neuromas and intestinal ganglioneuromas, and often a marfanoid habitus and other skeletal abnormalities.

MEN4 – A relatively new MEN variant and related to the CDKN1B gene, similar to MEN1 but normally only 2 of the 3 Ps, parathyroid and pituitary. Also referred to as MENX Possible association with tumors of the adrenals, kidneys, and reproductive organs.

What is particularly distinctive with MEN is that they are inherited disorders (familial).  That means that they can be passed down in families, with each child of an affected parent having a 1 in 2 or 50% risk of inheritance. Consequently genetic screening/testing is normally undertaken in established MEN families and those at risk of MEN.

Associated Issues

You may also have heard of other rare NETs with a familial aspect, in particular Pheochromocytomas (adrenal gland tumours) and Paragangliomas (outside the adrenal gland),  Not all are inherited and I mention them because of the connection with MEN2a and 2b.

Further information

I’m grateful to my friend and MEN patient Linda Hageman for supporting my blog activities and also for allowing me to join the AMEN support group to learn more.  This is one of the friendliest and well run support groups I’ve seen.  On this site, you will find Dr Mark Lewis, an Oncologist and MEN patient who supports Linda (who is a Nurse) with a ‘Ask the Doctor’ section on their website.

There are other organisations including one specifically for Pheochromocytomas and I’m grateful to Jennifer Shepard for featuring my nutrition blog series.

Complex area.

You may also enjoy my article on Genetics and Neuroendocrine Cancer.

Thanks for reading

Ronny

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