I was never diagnosed with Irritable Bowel Syndrome (IBS) but sometimes I feel like I now have it. I know many others feel the same way. But when I look at the alternatives, I can’t help thinking it’s a small price to pay given that one of them might be a slow degrading quality of life until shuffling off this mortal coil. If I had the choice again, I would still take the surgery.
Before the article continues, let me be clear – I’m not suggesting this is a potential treatment for NET patients with post abdominal surgery side effects or side effects of any other treatment, nor am I suggesting it’s a potential treatment for those with carcinoid syndrome diarrhea. I publish it because there is a connection to serotonin and it may be a useful read for the more curious amongst us. In fact, since publishing I’ve been contacted by several people telling me they are aware of the drug having been treated with it for nausea.
I once wrote about IBS in an article entitled “Were you irritated by your misdiagnosis” (click the link to read). This was written after I completed an online IBS course. I wrote the article in a balanced way in an effort to explain why many patients are misdiagnosed with IBS in the lead up to the correct diagnosis some time later. This is an issue with other conditions, not just NETs. It was also designed to capture IBS readers and offer them a chance to review their diagnosis to ensure there wasn’t anything else they might try to double-check (markers and scans mainly).
A new drug on trial for IBS
Given the connection between NETs and IBS, I was really interested to see this in a UK national newspaper and I subsequently researched for some formal papers to back up the headline. What I found most interesting was the suggestion that a drug designed to inhibit serotonin was involved (…… but read on rather than get too excited).
Diarrhea – the IBS and NET Effect
Diarrhea is a big feature of IBS although there are several types including diarrhea mainly, constipation mainly and a mixed of both – you can read more in my IBS article linked above. Diarrhea is also a big feature of several of the NET Syndromes, in particular Carcinoid Syndrome. It is known that the cause of carcinoid syndrome diarrhea is the oversecretion of serotonin. This makes is quite distinct from other reasons for diarrhea, including but not limited to side effects of intestinal surgery (as one example).
Clinical Trial: Treatment of IBS with diarrhoea – titrated ondansetron (TRITON)
What is ‘ondansetron’. It’s actually a powerful anti-sickness drug given to cancer patients and some of you may recognise it as ZOFRON. Interestingly it’s a serotonin receptor (5-HT3) antagonist (5HT3-RA) for antineoplastic chemotherapy-induced nausea and vomiting. Ondansetron is a drug which blocks the 5-HT receptor, which is used to treat nausea and sickness, and has an excellent safety record. Other 5HT3-RAs include Tropisetron, Granisetron, Dolasetron, Palonosetron, Ramosetron (the group of drugs in the class known as 5HT3-RAs are known a ‘setrons’).
It is being offered to those with irritable bowel syndrome (IBS), helping to ease the most embarrassing and painful symptoms of the condition. According to the Daily Mail, if the trial is successful, it could throw open the doors to the first targeted treatment for the millions of IBS patients with bloating, abdominal discomfort and urgent bowel movements. Two people on the trial are featured in the newspaper article reporting good outcomes.
Information on the Trial. Researchers are hoping to recruit 400 volunteers in the UK aged over 18 who have IBS to take part in the 12-week study. You can read more about the trial in the reference documents below.
I guess many of you will now be thinking that but I advise not to get too excited as things are never that straightforward. However, if I was a pharmaceutical involved in NET research, I would certainly be watching this trial carefully. None of us know the interaction between NETs, NET treatments and titrated ondansetron and its mechanism of action. It may be more directed at brain and central nervous serotonin rather than gut serotonin which is mainly the issue with carcinoid syndrome diarrhea, i.e. it may not work in the same way and/or have the same effect as other approved NET drugs such as somatostatin analogues (Octreotide/Lanreotide) and tryptophan 5-hydroxylase (TPH) inhibitors such as XERMELO.
Still, it’s an exciting trial.
I will keep this article live for any developments. Finally please note this is not in any way medical advice and not a recommendation to try these drugs to control your diarrhea.
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.
Incoming Questions
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.
Example:
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.
Anon
Patient Forums
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.
2. 5HIAA is a hormone marker for the most common type of NET, particularly if the patient is presenting with flushing and diarrhea. Many NETs have associated syndromes and hormone markers can be a guide to help with diagnostics. Read more about 5HIAA and other hormone markers for different types of NET and different syndromes 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.
Eight years ago today, I was sat in front of a secondary care consultant, his speciality was colorectal. I asked specifically for this consultant for two reasons, firstly, he carried out a colonoscopy some 20 months previously which turned out to be negative. Secondly, my GP had referred me to the iron deficiency anaemia clinic, and they wanted to do ….. a colonoscopy. I changed that plan because this “non-issue” was dragging on; quite frankly I wanted it to be resolved quickly, and I wanted it to be resolved in my favour – after all, I wasn’t actually ill!
Rewind two months, I had an incidental set of blood tests ordered by a nurse following a routine visit to my local medical centre (……. “I think I’ve lost a bit of weight“). My haemoglobin was low (even lower on repeat testing). The GP compared my results to someone in their eighties with malnutrition. In hindsight, I should have been alarmed by that statement but instead I went on holiday to Barbados. Apparently low haemoglobin is a sign of iron deficiency anaemia. I suspected it would pass, either my blood results would revert to normal naturally, or they would after a prescription for some pills. That’s what normally happens, isn’t it? I was so indifferent to the issue, I even delayed the blood tests by three weeks.
Back to 8th July 2010 ….I hadn’t really given him many clues but within minutes of chatting with the secondary care consultant (who was armed with the results of the negative colonoscopy test), he said “what are you doing this afternoon“. I had no hesitation in saying “whatever you want me to do“. I’m still not getting it as I saw this as a chance to get an all clear, get some pills, get back to normal. To cut a long story short, the results confirmed I had a metastatic cancer. If you can see it, you can detect it.
Following the scan results, I had a dozen other tests to narrow it down to Neuroendocrine Cancer (eventually confirmed by biopsy). During these 2 weeks of tests, I finally confessed for the first time that I had been experiencing facial flushing and intermittent diarrhea. In those days, I wasn’t really in tune with my body.
I had been sitting on a beach in Barbados sipping piña coladas with my wife and neither of us had any inkling that I had a serious life threatening illness and that it had been growing inside of me for some years. Slow but sneaky? You betcha. They did some damage too – check out my treatment summary here.
I remain thankful to all those involved in the triggering of my ‘incidental’ diagnosis. The Nurse who ordered the ‘just to be sure’ blood tests, the GP who immediately referred me to secondary care (increased my chances of being diagnosed with cancer), the secondary care specialist who was instrumental in getting to the bottom of the problem in double-quick time.
My intransigence, denial and withholding vital symptoms from the doctors didn’t really help – there’s a lesson for all there.
You can hear me talk about my diagnosis by clicking here
Diarrhea is a huge subject for NET patients, whether it’s caused by the tumor itself (i.e. a syndrome), due to treatment, knock on effects of treatment, or some other reason, it can dramatically limit qualify of life. Working out the root cause can be problematic even for medical teams. I wrote about these issues before in my article Neuroendocrine Cancer – the diarrhea jigsaw. So when I saw the data from a trial of something called enterade®, I was immediately drawn to investigate. I don’t normally write articles on over the counter commercial products but this one is an exception given that it has been classed as a medical food since 2012 and is also used to rehydrate patients undergoing radiotherapy and chemotherapy for cancer (so not just for NETs).
What is enterade® ?
It’s a drink currently produced in 8oz bottles. It’s a first-in-class, glucose-free medical food i.e. it is intended to be used under the supervision of a healthcare provider. The solution comprises five critical amino acids – Valine, Aspartic Acid, Serine, Threonine, Tyrosine and electrolytes – potassium and sodium.
What does it do?
It’s designed to help manage debilitating gastrointestinal (GI) side effects. With no sugar to exacerbate the GI tract, enterade® supports the small bowel’s ability to absorb fluids, nutrients, and electrolytes and leads to improved digestive function. By helping to restore normal GI function, enterade® reduces diarrhea and dehydration, leading to a significant improvement in the patient’s overall quality of life and a healthier GI tract.
Is there evidence that it works?
Since May 2017, it’s been trialled by University of Kentucky Markey Cancer Center (MCC) for potential use by NET patients – trial coordinators include the well-known NET specialist Dr Lowell Anthony. The results so far are very interesting. The recent conference reported revised data as follows:
33 of 41 patients (80%) reported subjective improvement in diarrheal symptoms.
51% (21/41) reported more than 50% reduction in diarrhea frequency.
click here or on the poster below to see the trial poster data output.
click to read full screen
As you will see from the poster, there were a wide range of patient types including (but not limited to) small intestinal NETs, bronchial NETs, NETs of unknown primary, gastric NETS, pancreatic NETs and one high grade neuroendocrine carcinoma of the prostate.
A follow on Phase 2 trial is now recruiting with the following detail available:
1. Up to 30 patients will be recruited.
2. The trial is coordinated by Markey Cancer Centre, Kentucky.
3. There will be two cohorts, those with carcinoid syndrome and those without.
4. The trial will run from December 2018 to August 2020.
Click here to see the trial information – important to note the inclusion and exclusion criteria.
Please also note there’s a plan for a follow on trial covering more locations. I will update further when known.
Can I buy Enterade now?
The product is available in North America on Amazon.com, www.enterade.com and 1-855-enterade. However, the parent company (Entrinsic Health) recently announced a partnership with global company Nestlé Health Science to provides worldwide commercial license and supply agreement for enterade®. The announcement is linked here:
NORWOOD, Mass., November 15, 2018 – Entrinsic Health Solutions (EHS), an innovative health sciences company, today announced that they have entered into a partnership with Nestlé Health Science (NHSc), a global innovative leader pioneering premium-quality, science-based nutritional health solutions. The partnership gives NHSc the exclusive rights to market EHS’s enterade® product.
Disclaimer
Please note this is not a recommendation to go out and buy the product. It is actually described as a ‘medical food’ and is formulated to be consumed or administered under the supervision of a physician.
3. Recent output from ASCO 2018 – click here. (contact data update for 2018)
4. If you are interested in more information about how enterade® works, check out this short video
Disclaimer
Please note this is not a recommendation to go out and buy the product. It is actually described as a ‘medical food’ and is formulated to be consumed or administered under the supervision of a physician.
This is an excellent and positive video based overview of where we are with the Management of NETs. This is a presentation from a NET Specialist (who some of you may know) presenting to a “GI Malignancies” conference. This is therefore not only awareness of NETs, it’s also some good education for non NET GI experts who may only know the very basics. Useful for patients too! I met Dr Strosberg in Barcelona (ENETS 2017) and thanked him for his presentational and scientific paper output which I often use in my articles.
The classification picture is good as it explains the different facets of NETs and how NETs are classified and categorised in a general way – not seen it done this way before. Slightly out of date as it does not adequately convey the possibility of a well differentiated high grade recently classified by the World Health Organisation – read more here.
Amazingly it is delivered without using the word ‘carcinoid’ other than in reference to syndrome, indicating it can be done and is something also being reflected in all my posts to ensure they are up to date with the latest nomenclature. It’s also a good example for GI doctors as this branch of medicine is often involved in NET diagnostics and surveillance.
Excellent update of all the trials which have introduced treatments in the last decade.
Great update and worth the 30 minutes it takes to watch – you can view it CLICK HERE.
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
QOL Improvements in NETTER-1 Phase III Trial in Patients with Progressive Midgut Neuroendocrine Tumors. (I think this is well-known but no harm in repeating it!)
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.
Graphic courtesy of Ellie McDowell
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 Neuroendocrine”,
“Neuroendocrine Carcinoid”,
“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.
Myth 5: Neuroendocrine Neolasms are rare
Not true. As a collective grouping of cancers, this is no longer accurate. Read more here. Also check out my post about the “Invisible NET Patient Population“.
Myth 6: Steve Jobs had Pancreatic Cancer
Not true. Steve Jobs had a Neuroendocrine Tumour of the Pancreas. Ditto for a few other famous names. Read more here.
The last few years have reminded me that life is fragile
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
Thanks for reading
Ronny
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In the last 12-24 months, there seems to have been announcement after announcement of new and/or upgraded/enhanced diagnostics and treatment types for Neuroendocrine Cancer. Scans, radionuclide therapies, combination therapies, somatostatin analogues, biological therapies, etc. Some of the announcements are just expansions of existing therapies having been approved in new (but significant) regions. Compared to some other cancers, even those which hit the headlines often, we appear to be doing not too badly. However, the pressure needs to stay on, all patients need access to the best diagnostics and treatments for them; and at the requisite time.There’s even more in the pipeline and I’m hoping to continue to bring you news of new stuff as I have been doing for the last year.
Some of these new diagnostics and treatments will benefit eligible patients who are in diagnosis/newly diagnosed and also those living with the disease. As we’re now in our awareness month, let’s recap:
Scans
Many NET Patients will undergo a nuclear scan to confirm CT results and/or to detect further neuroendocrine activity. Basically, a nuclear substance is mixed with a somatostatin analogue, injected into the patient who is then scanned using a 360-degree gamma camera. As gamma cameras are designed to show up radioactive activity; and as Neuroendocrine Tumour cells will bind to the somatostatin analogue, it follows that the pictures provided will show where Neuroendocrine tumours are located. Many people will have had an ‘Octreotide’ Scan (or more formally – Somatostatin Receptor Scintigraphy) which is still the gold standard in many areas. The latest generation of nuclear scans is based on the platform of the Gallium (Ga) 68 PET Scan. The principles of how the scan works is essentially as described above except that the more efficient radioactive/peptide mix and better scan definition, means a much better picture providing more detail (see example below). It’s important to note that positive somatostatin receptors are necessary for both scans to be effective. Europe and a few other areas have been using the Ga-68 PET scans for some time (although they are still limited in availability by sparse deployment). The latest excitement surrounding this new scan is because they are currently being rolled out in USA. Read about the US FDA approval here. You may hear this scan being labelled as ‘NETSPOT’ in USA but this is technically the name for the preparation radiopharmaceutical kit for the scan which includes a single-dose injection of the organic peptide and the radionuclide material. Take a look at a comparison of both scans here:
Octreoscan output vs Gallium 68 PET output
This slide from a recent NET Research Foundation conference confirms the power of more detailed scanning.
Peptide Receptor Radionuclide Therapy (PRRT)
Similar to above, this treatment has been in use in Europe and other places for some time but is also to be formally deployed in USA if, as is expected, the US FDA approval is positive at the end of this year (Read here). In the most basic terms, this is a treatment whereby a peptide is mixed with a radionuclide and is drip fed over a number of treatments (normally up to 4 spaced out over a year). The concept of delivery of the ‘payload’ to the tumours is actually very similar to the preparation for a radionuclide scan as described above, the key difference is the dosage and length of exposure whilst the tumours are attacked. Once again, receptors are important. The NETTER series of trials showed good results and this is an excellent addition to the portfolio for those patients who are eligible for this treatment. Fingers crossed for the US FDA announcement due by the end of this year. Also fingers crossed that PRRT returns to the NHS England & Wales portfolio of available treatments next year. The Carcinoid Cancer Foundation has an excellent summary of PRRT here.
PRRT and Chemo Combo
Whilst on this subject, I also want to highlight the innovative use of combo therapies in Australia where they are combining PRRT and Chemo (PRCRT). I blogged about this here:
Somatostatin Analogues and their Delivery Systems
Somatostatin analogues are a mainstay treatment for many NET Patients. These drugs target NET cell receptors which has the effect of inhibiting release of certain hormones which are responsible for some of the ‘syndromic’ effects of the disease. Again, receptors are important for the efficacy of this treatment. You can read the ‘geeky’ stuff on how they work here. These drugs mainly comprise Octreotide (provided by Novartis) and Lanreotide (provided by Ipsen). The latter has been around in Europe for 10 years and was introduced to North America earlier this year. Octreotide has been around for much longer, almost 17 years. When you consider these peptides have also been used to support nuclear scans that can detect the presence of tumours; and that studies have shown they also have an anti-tumour effect, they really are an important treatment for many NET Patients. I’ve blogged about new somatostatin analogues in the pipeline and you can read this here. This blog also contains information about new delivery systems including the use of oral capsules and nasal sprays (…….. very early days though).
Treatment for Carcinoid Syndrome
For maintenance and quality of life, the release of a Telotristat Ethyl for Carcinoid Syndrome is an exciting development as is the first new treatment for Carcinoid Syndrome in 17 years. This is a drug which is taken orally and inhibits the secretion of serotonin which causes some of the symptoms of the syndrome including diarrhea. It must be emphasised it’s only for treating diarrhea caused by syndrome and might not be effective for diarrhea caused by other factors including surgery. Read about how it works and its target patient group in my blog here.
Oncolytic Virus
The announcement of a clinical trial for the Oncolytic Virus (an Immunotherapy treatment)specifically for Neuroendocrine Tumours is also very exciting and offers a lot of hope. Click the photo for the last progress update.
Everolimus (Afinitor)
Earlier this year, AFINITOR became the first treatment approved for progressive, non-functional NETs of lung origin, and one of very few options available for progressive, non-functional GI NET, representing a shift in the treatment paradigm for these cancers. It’s been around for some time in trials (the RADIANT series) and is also used to treat breast and kidney cancer. It’s manufactured by Novartis (of Octreotide fame). It has some varying side effects but these appear to be tolerable for most and as with any cancer drug, they need to weighed against the benefits they bring.
In technical terms, AFINITOR is a type of drug known as an ‘mTOR’ inhibitor (it’s not a chemo as frequently stated on NET patient forums). Taken in tablet form, it works by blocking the mTOR protein. In doing so, AFINITOR helps to slow blood vessels from feeding oxygen and nutrients to the tumour.
Check out Novartis Afinitor website for more detailed information. There’s an excellent update about AFINITOR rom NET expert Dr James Yao here. The US FDA approval can be found here.
Summary
………. and relax! Wow, I’ve surprised myself by collating and revising the last 12-24 months. Dr James Yao also agrees – check out his upbeat message in the attached2 page summary. You may also like another upbeat message from Dr Jonathan Strosberg by clicking here.
Neuroendocrine Cancer – who’d have thought it? ….. a bit of a dark horse.
Thanks for reading
Ronny
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did you hear the one about the constipated NET Patient?
In my neck of the woods, “did you hear the one about the ………” is normally a precursor to a witty comment, or a joke. However, constipation for NET patients is not actually funny – read on.
Certain types of Neuroendocrine Cancer are very heavily associated with diarrhea, either as a symptom of one of the NET Syndromes (yes there is more than one …..); or as a result of surgery or certain other treatments. Occasionally, these symptoms and side effects can all combine to make it quite a nasty and worrying side effect.
I must admit to being surprised to find myself with feelings of constipation from around 4-5 years after my treatment and I set about trying to find out why that might be. To understand why I got to this stage, I assessed the history of my treatment and what I changed in an attempt to improve my Quality of Life (QoL) – I feel there is a strong connection.
When I underwent my primary surgery (Nov 2010), my surgeon said it would take months for my ‘digestive system’ to return to some form of normality. I soon found out what he meant, I seemed to be permanently affixed to a toilet seat (plenty of reading opportunities though ….. every cloud!). I suddenly realised that I needed to start looking seriously at my diet. I did find some improvements by trying to eat things that would bulk up my stools vs trying to avoid things that might increase frequency (i.e. I wanted a reduction in frequency combined with a bulkier stool). Eventually, I settled on a regime for the first couple of years and to be honest, I didn’t need to change my diet in any radical sense. I was also determined not to take any medication (I was taking enough) and wanted this to work as naturally as possible.
Things were still not ideal and in 2013, I even remember saying to my Oncologist that although I was never misdiagnosed with IBS, I felt like I now had it. I decided to attack this issue following professional advice from one of the eminent experts in the NET specialist dietitian world – Tara Whyand. My regime was now based on science (although it isn’t really an exact type!), that is checking the ‘at risk’ nutrient levels were OK (particularly ADEK and B12), taking supplements where necessary to help with deficiencies, and tackling things such as malabsorptionand diet.
The patient has a big part to play in any improvement strategy, so in 2013/14 I experimented more and completely changed my breakfast and lunch regime to oatmeal/porridge and toast which made a significant difference. I started to avoid eating large meals and I reduced fat consumption generally. I started taking probiotics to counter the effect of any bacterial imbalance as a result of my surgery (i.e. to combat SIBO). To keep track of everything, I set up and maintained a detailed diary to help identify things making it worse, tinkering as I went along. For those who are contemplating this sort of strategy, let me tell you – it takes time, effort and patience!
I seemed to make excellent progress with ‘frequency’, which is down to once or twice per day – i.e. I felt like a normal bloke 🙂 Quality was not consistently good but I’m of the opinion, this may be something I need to live with. Stomach cramps are reduced, as is gas and bloating reduced (I’m fairly confident that is mainly down to probiotics). Happy days, my strategy has worked. I reduced my average daily ‘visits’ by 400% without any medicine.
However …. (have you noticed, there’s always a ‘however’ with NET cancer?).
Although I’m generally well, I did start to think in 2016 that the balance was not quite right. My ‘visits’ were starting to last longer due to a consistent feeling of incomplete emptying – i.e. movement is OK but is followed by what seems like constipation. Additionally, I’ve had several episodes of constipation and pain with no ‘movement’ for 24-36 hours. This happened in May, September and December 2016. Had 3 more episodes in 2017 and 2 so far in 2018. My diary now has numerous ‘zero’ entries in the daily bowel movements column, something I never thought I would see again in my lifetime!
When you’ve had small intestinal surgery, as many midgut NET patients have, this sort of thing can be extremely worrying. A bowel obstruction can be dangerous and I’d like to avoid additional surgery at this stage. The second occurrence was particularly severe and the pain lasted for 1-2 weeks. Fortunately, the issues eventually settled and appear to have been a result of a sluggish system, although my regular scans check to see if any issues in that area might have been contributing. (Note – lactulose (oral) is awful, will never touch it again!). I seem to remember a few years ago thinking constipation would be a luxury. I can assure you it isn’t – things need to keep moving, the opposite is much worse!
So … am I a victim of my own dietary regime success? Possibly. The GP who assessed my constipation and pain in September 2016 told me to stop taking a Calcium supplement which was prescribed by the same practice at the beginning of that year – Calcium can slow your system down apparently (…..the calcium is a long story but it was a counter to an osteoporosis risk that I have due to long-term use of blood thinners). I already get enough calcium (and vitamin D) through the normal channels plus supplements, so it was a low risk action. I tinkered with my diet again, reducing my fibre intake and then built up again slowly. Additionally, I could probably do with more water! Perhaps my Lanreotide is having some effect too? In 2018, I changed my bread to one with less fibre as a test, nothing to report so far.
Is it just me with constipation issues? No….. I carried out some covert searches on forums and found this issue has been mentioned numerous times.
I suspect we need science and some specialist NET research in this area, not sure the over the counter prescription is the optimum solution. I was therefore delighted to see a patient survey produced by NET Patient Foundation in conjunction with the Royal Free Hospital presented right in front of me in Barcelona at ENETS 2018. In this survey (which I remember completing), they found that the most self reported side effect of somatostatin analogues was in actual fact constipation (shock horror!).
The poster as presented at ENETS 2018 – featuring Tara Whyand
As you can see from the picture, the survey results came along with some pertinent advice which you will already find in some of my articles co-authored by Tara Whyand who was involved in the survey results analysis. Interestingly, Tara commented on the constipation figure pointing out that the constipated feeling may in fact be confused with ‘incomplete emptying’ as I indicated I was experiencing above. I think she’s right.
Abstract posted at ENETS 2018
I’m always skeptical about patient surveys as they tend to be gathered from a very small percentage of the actual patient population and tend to be sourced from those with the worst issues (something I call ‘situating the appreciation’). There’s a little skepticism in me about this particular survey, mainly because the results were not scientifically investigated i.e. were these self-reported side effects actually caused by somatostatin analogues or something else?
However, many of the things reported in this patient survey are issues that I know patients tend to talk about anecdotally in patient forums. Some of them are already listed on patient information leaflets (often without patients knowing I might add) so this is further confirmation of the official trial results. Wide variances or new unlisted issues probably need looking at though.
Despite some of these side effects being listed, I believe doctors need to provide more support for patients who experience these issues. So, even if constipation (or incomplete emptying) is not totally caused by somatostatin analogues, at least this survey should start up a dialogue.
p.s. I recently started taking Pancreatic Enzyme Replacement Therapy to combat some of the well known side effects of somatostatin analogues but not yet evaluated their overall impact with the above story. Read about this and a Q & A session with Tara Whyand in this article – click here
A team of researchers from Case Western Reserve University School of Medicine have used high-powered microscopes for the first time to view serotonin activating its receptor
Background
I’d never heard of Serotonin until I was diagnosed with Neuroendocrine Cancer in 2010. It is frequently discussed, often with contrasting views from the respondents. One common assumption/question is that it is responsible for many things that can go wrong with Neuroendocrine Cancer patients who have serotonin-producing tumours. “It’s the hormones” is an easy assumption to make or an easy answer to give in response to a complex set of circumstances. It’s difficult to get a definitive answer and the science behind the behaviour of our hormones isn’t really 100% tied down.
You may see serotonin referred to as a ‘neurotransmitter’, a ‘chemical’ and a ‘hormone’ – this is complex but it is my understanding that it can add context in respect the role/location of the serotonin, e.g. chemical and hormone are essentially synonymous and are endocrine related whereas neurotransmitter is concerned with the nervous system (the neuro in neuroendocrine) and the brain (more on this below). Consequently, I’ll keep this as basic as I can (author’s note on completion – it was not easy!).
Serotonin and NETs
One thing which is widely accepted and agreed…… Serotonin is definitely involved in Neuroendocrine Tumours, in particular, those resulting in carcinoid syndrome which can manifest as a number of symptoms including but not limited to flushing and diarrhea. Although serotonin is one of the main ‘hormones’ released in excess by certain NETs (mainly midgut), it is not thought to be the main culprit behind some of the symptoms produced by Carcinoid Syndrome. For example, flushing, the most common symptom (and a cardinal one) is thought to be caused by a number of hormones/peptides – too many to list but the main ones are histamine (particularly foregut), tachykinins (Substance P), bradykinins, prostaglandins …….. and I’m sure serotonin’s in there too! It does, however, appear to be massively guilty in causing carcinoid syndrome diarrhoea, desmoplasia, and carcinoid heart issues.
Where does Serotonin come from?
Serotonin’s technical name is 5-hydroxyltryptamine (5-HT). It is converted from 5-Hydrotryptophan (5-HTP) which is also known as oxitriptan. 5-HTP is a naturally occurring amino acid and chemical precursor as well as a metabolic intermediate in the biosynthesis of serotonin (…..and melatonin) from tryptophan. Tryptophan is interesting as that brings in one of the missing pieces of the jigsaw – food! Tryptophan cannot be manufactured in the body, it must be brought in via diet. There is no serotonin in food, it is only manufactured in the body.
Tryptophan in food enters the body and serotonin is created by a biochemical conversion process which combines tryptophan (essentially a protein) with tryptophan hydroxylase (TPH), a chemical reactor. I suspect other substances might be involved in that process. There are two forms of tryptophan hydroxylase – TPH1 and TPH2, which are encoded on two independent genes. TPH1 is linked to peripheral serotonin while TPH2 is related to brain serotonin.
While serotonin cannot cross the blood-brain barrier, tryptophan can, and once there, almost all of it is converted to serotonin. Unlike, peripheral setotonin where only a small percentage is used to generate serotonin. Just to emphasise that NET dietitians do not say to avoid foods containing tryptophan other than at the time of marker testing (see below andnutrition Blog 4). When you look at the role in brain serotonin, this might have an adverse effect.
Serotonin Inhibitors
The introduction of Somatostatin analogues (SSAs) such as Octreotide and Lanreotide, help reduce the secretion of “tumour-derived serotonin” by binding to its receptors on the outside of the cell. If you ever wondered why receptors are important, please check out my blog on this subject (click here).
I mentioned tryptophan hydroxylase (TPH) above and that is actually very interesting as this is how Telotristat Ethyl (XERMELO) is able to help with the symptoms of Carcinoid Syndrome diarrhea (not adequately controlled by SSAs) or where patients are unable to be treated by somatostatin analogues for whatever reason. It’s a potent inhibitor of TPH which will disrupt the manufacturing of tumour-derived serotonin. There is also evidence that it can help reduce the effects or halt the growth of the fibrosis leading to carcinoid heart disease. Slight digression but useful to aid/enhance understanding at this point. Read about Telotristat Ethyl here.
Serotonin and the Brain
There is constant discussion and assumption that serotonin-producing tumours are somehow causing depression, anxiety and rage. Not as simple as that, it’s way more complicated. Certain NETs can overproduce serotonin in the gut but the issues concerning depression and anxiety are normally associated with low levels of serotonin in the brain.
“Cancer anger” is a normal response to fear, despair and grief – a range of feelings which cancer brings into our lives. It can show as frustration, irritability, emotional withdrawal or aggression. You can feel it whether you have been diagnosed or you are a relative or friend. Cancer anger can happen at any stage of the illness, even years after treatment. I know that many people with cancer suffer from depression, anxiety and anger but they do not all have serotonin-producing tumours. What they do have is a life threatening and/or life changing condition which is bound to have an effect on mind as well as body. Hormones including Serotonin are natural substances found in the body and not just there to service NETs.
Serotonin is separately manufactured in the brain (~10%) and in the gastrointestinal tract (~90%). The serotonin in the brain must be manufactured in the brain, it cannot be directly increased or reduced external to the brain, i.e. it cannot be directly reinforced by gut serotonin (peripheral serotonin). It follows that ‘brain serotonin’ and ‘gut serotonin’ are held in separate stores, they are manufactured in those stores and remain in those stores – there is no cross-pollination. This is managed by something called the blood-brain-barrier (BBB). Therefore, excess serotonin from NETs does not infiltrate the brain. As low-level of ‘brain serotonin’ is often linked to depression, it also follows that it’s possible to have high levels of serotonin in the gut but low levels in the brain.
My simple way of thinking about such things as outlined above, is that low levels of tryptophan in the brain might be contributing to low levels of serotonin in the brain. To clarify that, I researched the reasons why there could be low serotonin in the brain. First, let’s dismiss any connection that the type of anti-depressant called Selective serotonin reuptake inhibitors (SSRIs) is involved. It’s thought that SSRIs work by increasing serotonin levels in the brain. Serotonin is a neurotransmitter (a messenger chemical that carries signals between nerve cells in the brain). We already discussed that it’s thought to have a good influence on mood, emotion and sleep. After carrying a message, serotonin is usually reabsorbed by the nerve cells (known as “reuptake”). SSRIs work by blocking (“inhibiting”) reuptake, meaning more serotonin is available to pass further messages between nearby nerve cells. So tryptophan or peripheral serotonin are not really involved.
It would be too simplistic to say that depression and related mental health conditions are caused by low serotonin levels (in the brain), but a rise in serotonin levels (in the brain) can improve symptoms and make people more responsive to other types of treatment, such as Cognitive Behaviour Therapy (CBT). It’s also too simple to suggest that NET patients get depression and anxiety due to all the “hormones” these tumours produce. Of course hormones can be involved in depression and anxiety but hormones aren’t their just for NET patients. Cancer patients without hormone secreting tumours also get anxiety and depression so it’s possible that NET patients can get depression and anxiety in the same way.
It should also be noted that the precursor to serotonin, tryptophan, does pass through the BBB and it is therefore possible that tryptophan depletion can lead to less availability in the brain for the manufacture of brain serotonin. Tryptophan depletion can be caused by dietary restrictions (i.e. lack of tryptophan foods) and also by the effects of certain types of tumours as excess serotonin is made leading to less availability of tryptophan. Both could lead to low serotonin in the brain as less tryptophan gets there. It follows that foods containing tryptophan remain important in order to help maintain normal brain serotonin levels.
Measuring Serotonin levels
Measuring levels of serotonin is important in both diagnosis and management of certain NETs – although it’s probably sensible to test all potential NET patients during diagnosis when the type of tumour is not yet known. Testing for tumour markers will differ between countries and within countries but the most common standard for testing Serotonin appears to be 5-HIAA (5-hydroxyindoleacetic acid) either via a 24-hour urine test or via a plasma version (mainly used in USA but now creeping into UK). 5-HIAA is the output (metabolite) of 5-HT (Serotonin). Not to be confused with the less reliable ‘serum serotonin’ which is a different test.
Another frequently asked question about serotonin tests is whether they are testing the amount in the brain or the gut. The answer is …… they are testing the levels in the blood. Furthermore, if you are measuring serotonin as an indicator for Carcinoid Syndrome, it has to be remembered that the majority of serotonin is in the gut, so even if serotonin levels in the brain were being measured alongside the gut levels, I don’t believe it would influence the result in any significant way (but I have no science to back that up). It also has to be remembered that serum serotonin and 5HIAA are not absolute tests, they are not 100% sensitive, they are simply indicators of a potential problem. There are methods of measuring brain serotonin but it is very complex and beyond the purposes of this article. However, I would just add that it is the reuptake of Serotonin in the brain (plus some other stuff) that can cause depression, not the actual level or amount in the brain.
I intentionally did not mention the other common test (Chromogranin A) or other markers as they are measuring different things but you can read about in my Testing for Markers blog.
Serotonin Video with myself and Dr Mike Morse
I made a video in 2019 with Dr Mike Morse sponsored by Lexicon Pharmaceuticals, Inc. It’s all about Carcinoid Syndrome with a slant towards hormones, in particular Serotonin. Entitled “Likely Suspects: How Hormones May Lead to Carcinoid Syndrome – What People Living With Carcinoid Syndrome Need to Know”
You need to register to watch although some of you will already be registered and just need an email to login to see the this webcast. The one I’m featured in is the latest in a series on the subject and I’d like to break the record for views please! Please help me achieve this 💙 I would also love to get your feedback and sincerely hope you will find the time to listen in. Please also find the time to complete the survey at the end. Thanks
I personally don’t see myself as ‘disabled’ but I do have an invisible illness. I’m fit, can walk for miles, I even look quite healthy. However, I live with the consequences of Neuroendocrine Cancer. These consequences differ from person to person but I know that some people with this disease have even met the criteria to be officially classed as ‘disabled’ through government schemes. Judging by what I read, I have less debilitating issues than others, so I feel quite fortunate. That’s not to say I don’t have any issues at all – because I do!
Situation normal, right?
I was therefore delighted to see news of an initiative supporting invisible illnesses by Asda (for those outside UK, Asda is a major UK wide supermarket chain). Asda have now recognised that many conditions can be classed as ‘invisible disabilities’ and this need is now recognised in the availability of toilet facilities (see picture below). This is particularly relevant to my own disease, all types of Inflammatory Bowel Disease (Crohn’s, Ulcerative Colitis) or anyone who has issues due to the consequences of their cancer or treatment (e.g. GI surgery, Chemo, Radiotherapy).
I wrote an earlier blog on this subject called “Things are not always how they seem“. This was a great ‘invisible illness’ awareness message in the form of a reference to a newspaper article about a lady who had Inflammatory Bowel Disease (IBD) and was ridiculed by someone who saw her use a disabled toilet clearly unaware of her invisible illness. This is definitely worth a read!
I also wrote a blog about my own concerns focussing in on the issue of ‘Stomach Cramps’. This is something that causes me issues from time to time and I dread a painful occurrence if I’m ‘out and about’. I generally don’t let Cancer stop me doing stuff. Consequently, I will still visit remote places as I have done so for the last few years and have intentions of continuing to do so in the future. Fortunately I have been lucky with my experiences to date. If I’m out and about including on holiday, I have no reservations about waltzing into hotels or restaurants where I know there will be toilet facilities. I’ll also use a disabled toilet if others are not vacant. My worst and most painful experience was in 2014 whilst I was walking along Hadrian’s Wall in remote Northern England – this is covered in my blog “My stomach sometimes cramps my style“.
I have not yet been challenged in my use of toilet facilities (without being a customer) but I always carry some ‘Get me out of jail’cards just in case. I have two, one from NET Patient Foundationand one from Macmillan Cancer Support. You can order these online (links given) and I’m sure other national advocate organisations do similar things.
I applaud Asda for their initiative. Lets hope it catches on anytime soon!
Telotristat Ethyl is an extremely significant introduction to the treatment of Carcinoid Syndrome diarrhea. It’s the first addition to the standard of care in more than 16 years and the first time an oral syndrome treatment has been developed. The drug was previously known as Telotristat Etiprate but was changed to Ethyl in Oct 2016. ‘Etiprate’ was previously a truncation of ‘ethyl hippurate’. The brand name is XERMELO®
UPDATE MARCH 2018
The March 2018 issue of Clinical Therapeutics provides the first report of the effects of XERMELO on changes in weight in patients with neuroendocrine tumors (NETs) and carcinoid syndrome that participated in the TELESTAR study. You have to remember that XERMELO is approved for those with carcinoid syndrome diarrhea not adequately controlled by somatostatin analogues (author’s note – i.e not for diarrhea caused by (say) side effects of surgery).
Of the 120 patients with weight data available, up to 32.5% of patients treated with XERMELO experienced significant, dose-dependent weight gain (≥3% from baseline). Only 5.1% of patients on placebo experienced weight gain. Importantly, patients with weight gain experienced improvement in carcinoid syndrome control, as seen in reduction of bowel movement frequency and in parameters of nutritional status associated with positive changes in patient-reported outcomes compared with patients with stable weight or weight loss. Those patients also experienced reduced u5-HIAA levels. Patients with weight gain also experienced fewer serious adverse events than patients with stable weight or weight loss.
(see link below)
Who is the drug for?
The drug may be of benefit to those whose carcinoid syndrome diarrhea is not adequately controlled by somatostatin analogues (Octreotide/Lanreotide). It doesn’t replace somatostatin analogues – it is an additional treatment alongside (although I have heard of patients in the US being subscribed who are not receiving somatostatin analogue treatment)
On 19 September 2017,the European Commission approved Xermelo® (telotristat ethyl) for the treatment of carcinoid syndrome diarrhea in patients inadequately controlled by somatostatin analogue therapy after the scientific committee of the EMA (known as Committee for Medicinal Products for Human Use (CHMP)) adopted a positive opinion recommending the approval of Xermelo® (telotristat ethyl) 250 mg three times a day for the treatment of carcinoid syndrome diarrhea in combination with somatostatin analogue (SSA) therapy in adults inadequately controlled by SSA therapy. The Ipsen press release is here. Clearly some action will be required in EC national countries before the drug becomes available through the appropriate healthcare systems.
On 17 Oct 2018, Health Canada announced approval for Canadian NET patients – click here.
For all other countries please note that Ipsen will pursue a worldwide regulatory plan for marketing authorisation submissions in the territories in which it operates. Once approved, Ipsen will be distributing the drug in all countries less USA and Japan where Lexicon retains the rights. Outside USA and Europe will be constrained by national approval timelines.
How does it work?
In the simplest of terms, the drug is an inhibitor of the enzyme tryptophan hydroxylase (TPH). TPH is the rate-limiting enzyme in serotonin synthesis which converts tryptophan (an essential amino acid which comes from diet) to 5-hydroxytryptophan, which is subsequently converted to serotonin, one of the main causes of carcinoid syndrome effects including carcinoid heart disease. The trial data indicates that Telotristat ethyl significantly reduced the frequency of bowel movements. Furthermore, it was also associated with “significantly reduced levels of urinary 5-HIAA“, a marker for systemic serotonin levels, which are typically elevated in severe carcinoid syndrome. Essentially it works by reducing the manufacture of Serotonin so it’s it may not have any effect on diarrhea not caused by syndrome (i.e. post surgery etc).
Resources for your perusal:
You can read more about the trial data in a summary by Dr Matthew Kulke (Dana Farber) by CLICKING HERE (latest review from 2017 ASCO).
There is also an excellent summary in video form by Dr Lowell Anthony (University of Kentucky) by CLICKING HERE. (“any reduction in diarrhea is meaningful“).
The detailed output from the trial (results) can be found by CLICKING HERE.
Great 2016 article from ASCO (American Society of Clinical Oncologists) can be found by CLICKING HERE.
I made a video in 2019 with Dr Mike Morse sponsored by Lexicon Pharmaceuticals, Inc. It’s all about Carcinoid Syndrome with a slant towards hormones, in particular Serotonin. Entitled “Likely Suspects: How Hormones May Lead to Carcinoid Syndrome – What People Living With Carcinoid Syndrome Need to Know”
You need to register to watch although some of you will already be registered and just need an email to login to see the this webcast. The one I’m featured in is the latest in a series on the subject and I’d like to break the record for views please! Please help me achieve this 💙 I would also love to get your feedback and sincerely hope you will find the time to listen in. Please also find the time to complete the survey at the end. Thanks
When I was diagnosed, I wasn’t feeling ill. In hindsight, I now know some of the signs were there, I just put up with them. Neuroendocrine Cancer had laid a trap for me and I fell right into it. You see, Neuroendocrine Cancer can be very quiet and unobtrusive. It also plays the ‘long game’ and will sometimes take years before it’s finally discovered. It is very very very sneaky.
Not satisfied with loitering in your small intestine, appendix, lungs, stomach, pancreas and a host of other places, it wants to reach out to your liver, your lymph nodes, your bones, bung you up with fibrosis, and get into your heart where it can cause the most damage. It will also try to get into your head, metaphorically speaking – however, it will also try the physical route.
As it spreads, it can become noisier through growth but also by secreting excess amounts of hormonesand other substances. It knows that tumour growth and these excess hormones and substances will mimic routine illnesses such as IBS, diarrhea, stool changes including steatorrhoea, stomach cramps and bloating, asthma, facial flushing, menopause, weight loss, anaemia, fatigue, tachycardia (fast heart beat), pain, and nausea – a real witch’s brew of symptoms. These may manifest themselves as common endocrine conditions e.g. it can mess with your blood sugar and thyroid levels. These are a few examples, there can be many others – it’s a real witch’s brew of symptoms. Neuroendocrine Cancer thinks this is great because it fools doctors into misdiagnosing you with something else which means it can continue to grow undetected and unfettered, spreading further inside you.
If nothing is done to stop its relentless growth, it will eventually kill.
However, sometimes an inquisitive doctor or nurse upsets its progress by thinking ‘outside the box’. Neuroendocrine Cancer hates when people are aware of its devious nature and hates when people know which tests can be used to find it and which treatments are best to attack it. Inquisitive, proactive and determined patients can also add to this effect and sometimes a bit of luck is involved.
It doesn’t give up easy and tries to work around your treatment. It knows your treatment will come with certain consequences and it will try to exploit this situation by keeping you guessing between cancer activity and these consequences. It really hates observant medical staff and patients, particularly those who understand Neuroendocrine Cancer.
Unfortunately for Neuroendocrine Cancer, there is now more knowledge about its devious activities and the latest statistics indicate it’s starting to be caught earlier. Nonetheless, we cannot afford to become complacent.
Neuroendocrine Cancer hates awareness and it will be extremely happy if you don’t share this post.
OPINION. Nutritional issues are one of the biggest challenges affecting most Neuroendocrine Cancer patients. It is also a key factor in maintaining a decent quality of life and for most countries without adequate NET Specialist Dietitian support, it remains an unmet need. In this article, I’m discussing the use of probiotics to combat the potential issue of small intestine bacterial overgrowth (SIBO) in Neuroendocrine Tumours.
When I first indicated this nutrition series was under construction, a few people got quite excited anticipating me to produce advice on what to eat. However, that was never my intention. What people should or should not eat is such a varied problem (or solution?) that anything I said would only really be of help to those for whom it worked – this area is not an exact science. I’ve seen several ‘what to or not to eat’ publications/articles out there aimed at NET patients; some more up to date than others – all I would say is to interpret them carefully.
What my nutrition series actually covers is what causes the nutritional related issues and to a certain extent, try to work out how to tell if these issues are caused by either treatment or an associated syndrome, leaving fellow patients to make up their own minds about what to eat; or arm themselves with the necessary knowledge whether this applies to them or not.
The first two articles in the series were Article 1 – Vitamin and Mineral Challenges and Article 2 – Malabsorption. These remain popular and have a constants stream of views – no surprises as these are well known side effects of many types of NETs…… or at least they should be well known.
This particular article “Gut Health” is not as ‘clear cut’ or simple as the first two and I suggest you read Articles 1 and 2 first if you are not familiar with the issues. Again I’m grateful to Tara Whyand (NET Specialist Dietician and researcher from Royal Free London) for some of the input below. Although I marked this with ‘Opinion’, some of it has references but I still decided to use ‘Opinion’ as the science is not yet 100%.
What is the “Gut” ?
When I first met my surgeon, I found one of his favourite words was ‘Gut‘. Like me before diagnosis, many of you will have heard or used the word but in an intentionally non-medical context, e.g. guts (bravery), ‘gut feeling’ or ‘gut instinct’ (intuition). I’ll return to that theme later but when you look at these contextual uses of the word, it’s no surprise why some scientists refer to our gut as a ‘second brain’.
I always thought the gut referred to just the ‘belly’ area but in medical parlance, the gut has a much bigger geography. It is sometimes used interchangeably with the term Gastrointestinal (GI) Tract and stretches from the throat to the anus and is responsible (in the most general terms) for food intake, digestion/absorption, waste processing and finally waste ejection. NET patients should be familiar with the terms ‘foregut’, ‘midgut’ and ‘hindgut’ which are sometimes used to define the embryological origin and grouping of Neuroendocrine primary tumours, although the boundaries and constituent parts can vary from site to site. The inclusion of certain anatomical locations as a sub-section of the gut is clearly for convenience rather than anatomical accuracy (e.g. Lung).
This is a massive subject but I wanted to ‘cut to the chase’ in this article and focus on the use of probiotics to combat the potential issue of small intestine bacterial overgrowth (SIBO) in Neuroendocrine Tumours. The symptoms and signs of SIBO can be similar to they symptoms and side effects of treatment that many patients report anecdotally on patient forums. I also found the science is complex and not really 100% tied down.
Probiotics
One of the first pieces of advice I was given after my initial surgery was to take probiotics – to keep up my stocks of ‘good’ bacteria. I didn’t really understand why, I just complied. I started with the liquid drinks you can buy in most supermarkets and supplemented this by eating bioactive yoghurt. I didn’t really notice any difference from either but the yoghurt was nice to eat!
Tara Whyand then confirmed this advice when I first met her in 2012 at a NET Patient conference. In 2013 when I started looking for a new normal, I realised that the supermarket drinks and yoghurts were simply not enough good bacteria for my ‘new plumbing’, and decided to take a high-grade daily capsule containing 5 billion friendly bacteria multiple strains (Tara does recommend at least 2 billion and multiple strain). Within weeks I was noticing a difference in bowel motility although I confess to changing other elements of my lifestyle at the same time given that I was embarking on finding my new normal. Nonetheless, I sense probiotics are helping and I won’t be reducing or stopping them any time soon. If you look at several NET specific dietician/nutrition presentations, most appear to promote the use of probiotics for NET patients.
Bacteria
One of the terms you find in this complex area is the ‘human gut microbiota‘, sometimes known as ‘gut flora‘. Our ‘gut’ harbours a complex community of over 100 trillion microbial cells, approx 3% of our body mass! The human gut microbiota is known to have an influence on every part of our body (including the brain…..) and disruption of this ‘community’ has been linked with several gastrointestinal conditions such as Inflammatory Bowel Disease (IBD) and obesity.
Probiotics are said to help keep the balance and mix of bacteria stable within the gut which can be affected by many different factors, including the use of antibiotics, aging, illnesses (such as IBD), following infective gastroenteritis and (of interest to NET patients) after cancer treatment or gastrointestinal surgery. {1} Incidentally, the reference here is authored by Tara Whyand and Professor Martyn Caplin (a Neuroendocrine Tumour expert who also happens to be a Gastroenterologist). Useful reading if you have any of the conditions in the report or have had gut surgery (or like me you are a total geek!). They are also frequently used in Irritable Bowel Syndrome (IBS).
Small Intestine Bacterial Overgrowth (SIBO)
Another interesting area of research into something called Small Intestinal Bacterial Overgrowth (SIBO), a condition where the small intestine is populated by an abnormal amount and/or types of bad bacteria. It follows that probiotics (good bacteria) may be useful in combatting this by helping to maintain balance.
So how does SIBO potentially and specifically affect NET patients?
It can be caused or exacerbated by abdominal surgery to stomach, duodenum, pancreas or via whipples, small & large intestine,
poorly controlled diabetes,
the long-term use of Proton Pump Inhibitors (PPI) (e.g. omeprazole and lansoprazole, etc). Several studies link to these drugs including this one,
possibly long term use of antibiotics which can kill good bacteria.Some evidence of surgical involvement can be found here – this link – particularly the bit about the prevalence of patients who have had an “abdominal surgery” or an “Ileocaecal valve resection”. I guess that would include many NET patients? (this is a big article so just focus on table 1 near the beginning).
Symptoms vary for everyone from watery diarrhoea suddenly starting 20 times a day to just bloating and wind in both directions, to nothing at all. These symptoms are regularly reported by patients so working out the root cause might need some professional help.
Is there any testing for SIBO?
There is a test to check for SIBO is called the Hydrogen breath test. This test uses lactulose ingestion to measure the hydrogen in the breath. If SIBO is diagnosed, treatment is normally via antibiotics. However, advice is to leave a 2 hour gap between taking probiotics and antibiotics and a high dose multi-strain probiotic should be applied. Our friend Tara has done some work on this alongside Professor Martyn Caplin which was featured at ENETS 2017.
ENETS Research – Assessment of Small Intestinal Bacterial Overgrowth (SIBO) in NET Patients Abstract #1698
Introduction: SIBO is not uncommon in NETs. Hydrogen Breath testing (HBT) using glucose may be more sensitive to proximal SIBO as glucose rarely reaches the colon. Many NET patients are likely to have distal SIBO however, as factors such as ileocecal valve removal apparently increase distal SIBO risk. Thus glucose BT alone may limit sensitivity for detecting SIBO in some NET diagnoses.
Aim(s): Assess likely risk factors for SIBO. Assess sensitivity of additional lactulose HBT and CH4 BT.
Materials and methods: Retrospective data (n=55) of NET patients undergoing HBT was examined. Twelve patients (12/55) who tested negative for glucose HBT but continued to have diarrhoea +/- wind had repeat BT using lactulose. These patients had both H2 & CH4 BT.
Results: Midgut NET diagnoses were most frequently referred for BT (n=43, 78%). Twenty four (24/55, 44 %) had prior right hemicolectomy. Ten (10/24 ,42%) of those were SIBO positive. Ten patients were positive for HBT prior to being given the glucose substrate, they all had abdominal surgery in the past. Twelve patients who tested negative for glucose HBT had repeat testing using lactulose and measured both H2 and CH4 production. This led to an additional 3 (25%) positive results.
Conclusion: Abdominal surgery, especially right hemicolectomy increases the likelihood of a positive glucose HBT. Glucose may still be sensitive in those with risk factors for distal SIBO. Additional lactulose use with H2 and CH4 measurement increases the sensitivity in diagnosing SIBO.
I personally take a 5 billion dosage and am happy to recommend the source offline. However, in addition to obtaining from a reputable provider (i.e. in UK, MHRA approved supplier), there is evidence to suggest as long as it has some or all of the following strains that are widely available, they should provide benefit: Lactobaccilus plantarum, Lactobaccilus acidophilus, Lactobaccilus brevis, Bifidobacterium lactis and Bifidobacterium longum.
This article could have been 10 x longer! I didn’t even get to the bit about the relationship between the gut and the brain – perhaps another day?
None of this should be considered medical advice.
Article 1 – Vitamin and Mineral Challenges. This was co-authored by Tara Whyand, UK’s most experienced NET Specialist Dietician. This blog provides a list of vitamins and minerals which NET Cancer patients are at risk for deficiencies, together with some of the symptoms which might be displayed in a deficiency scenario.
Article 2 – Malabsorption. Overlapping slightly into Part 1, this covers the main side effects of certain NET surgical procedures and other mainstream treatments. Input from Tara Whyand.
Article 3 – ‘Gut Health’. This followed on from the first two blogs looking specifically at the issues caused by small intestine bacterial overgrowth (SIBO) as a consequence of cancer treatment. Also discusses probiotics. Input from Tara Whyand.
Article 4 – Food for Thought. This is a blog about why certain types of foods or particular foodstuffs can cause issues.
I also found myself smiling at the fact that flushing is connected with the toilet and a type of red warm feeling in the upper torso – the two main symptoms of the Carcinoid Syndrome associated with the most common type of Neuroendocrine Cancer. “Please flush after use” – erm…yes sure but actually – no thanks
In the past couple of years, I’ve read so many stories about the quite natural act of using a toilet (…..some more repeatable than others). I think if there was a ‘Bachelor of Science degree in Toiletry’, I might pass with First Class Honours.
I jest clearly but it’s strange that such a routine activity for most can actually become quite scientific in the world of Neuroendocrine Cancer and other ailments which might be described in some scenarios as invisible illnesses.
I also found myself smiling at the fact that flushing is connected with the toilet and a type of red warm feeling in the upper torso – the two main symptoms of the Carcinoid Syndromeassociated with the most common type of Neuroendocrine Cancer. “Please flush after use”– erm…yes sure but actually – no thanks 🙂
You’re kidding me!
When I read about some of the issues others deal with, I think I’m one of the luckier Neuroendocrine Cancer patients regarding these type of issues. I’m in reasonable condition considering the extent of my disease and my subsequent treatment. I put up with a number of irritants but I don’t seem to suffer as much as some appear to do. That said, I think I sometimes downplay my own issues though, I’m well known for ‘not frightening the horses’.
One thing that does worry me is the occasional stomach cramp. Hopefully, I’m not tempting fate as they seem to be vastly reduced in the past 3 years. They can sometimes be very painful and debilitating – normally resolved by going to the toilet (and hopefully one is close!). Handy if I’m in the house, not so handy if I’m on a plane, in town or anywhere where toilets are not in abundance. I did write a blog on this subject following a very painful episode on my Hadrian’s Wall 6 day adventure – ‘My stomach cramps my style’.
As I’ve had intestinal surgery, Bowel obstructions are a potential worry. To date, pain and sluggishness have always been just a bout of constipation. Read my article here. You can carry a card for the bowel obstruction risk courtesy of NET Patient Foundation – these guys have a card for most stuff.
I don’t suffer from ‘carcinoid syndrome induced diarrhea’ but long flights are one of the few times I take Loperamide (Imodium). For long drives and trips to town, I’m simply reliant on toilet availability. Normally, I just wander into hotels and restaurants and help myself. Sometimes I find only the disabled toilet is available and when it’s urgent I have no qualms about using it. Some of them are locked and you have to get a key – again I have no qualms about asking for access despite my outwardly healthy look – nobody has argued yet! If sufficiently urgent, I’m even prepared to ask to use the staff toilets in shops etc. I do have a card in my wallet, which again, I obtained from my friends in the NET Patient Foundation. I’ve not yet had to use it in anger. I also noticed that Macmillan are now doing something similar.
On the subject of urgent visits to the toilet. I recently wrote a blog about a lady with inflammatory bowel disease (IBD) and I suspect in a worse condition than most Neuroendocrine Cancer patients. She too looks outwardly healthy but this illness is clearly a major disability. I’d like to think this type of incident is not that common but her response to it was magnificent and it apparently went viral. Just goes to show that with invisible illnesses ‘Things are not always how they seem‘. The letter is brilliant.
For those who are interested, NET Patient Foundation also do a Carcinoid Crisis at risk emergency card to keep in your wallet/purse so that doctors can be forewarned of the aversion to anaesthetics etc. Mine is in my wallet at all times just in case.
what I mainly remember was my wife Chris holding my hand which gave me a great deal of much-needed comfort and security
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It was 10th November 2010 just after midnight. I gradually woke up after a marathon 9 hoursurgery – the first of what was to be several visits to an operating theatre. The last thing I remembered before going ‘under’ was the voices of the surgical staff. When I woke up, I remember it being dark and I appeared to be constrained and pinned down by the dozen or so tubes going in and out of my weak and battered body. I can still remember the feeling today, it was like I was pinned to the bed and I was completely vulnerable and helpless. However, what I mainly remember was my wife Chris holding my hand which gave me a great deal of much-needed comfort and security.
The build up to this day began on 26 July 2010 when I was given the news that I had metastaticNeuroendocrine Tumours and that the prognosis without any treatment wasn’t too good making the decision to have treatment a lot easier. I told my Oncologist to ‘crack on’ with whatever treatment would be required.
However, it wasn’t that easy and as I was yet to find out, Neuroendocrine Cancer isn’t a simple disease. I first had to undergo a plethora of other tests including specialist scans, blood and urine tests. The specialist scans (crucially) confirmed my tumours were ‘avid’ to a something called a ‘somatostatin analogue’. The scan also confirmed I had more tumours than initially thought. This was key to working out my treatment plan as I now had a grading, staging and I had the right tumour ‘receptors’ to assist along the way.
When I initially presented in May 2010, I hadn’t realised for some months that I was showing symptoms of one of the Neuroendocrine Tumour syndromes (in my case carcinoid syndrome‘. This was mainly facial flushing but thinking back, there was some diarrheaalbeit infrequent. The subsequent specialist blood and urine tests (CgA and 5HIAA respectively) were way out of range confirming both the diagnosis of tumour bulk and tumour activity respectively. The tumour activity (or function) is one thing which makes NETs different from most cancers and is caused by excessive secretion of specific hormonesapplicable to the primary location of the tumour. Thus why I had to be established on a ‘somatostatin analogue’ which is designed to inhibit the excessive secretion. I self-injected Octreotide daily for 2 months until the flushing was under control. When Neuroendocrine Tumours cause carcinoid syndrome, there is a risk of a phenomenon known as ‘Carcinoid Crisis’. This is the immediate onset of debilitating and life-threatening symptoms that can be triggered by a number of events including anaesthesia. As an additional precaution to prevent such complications, I was admitted on the 8th November 2010 in order to have an ‘Octreotide soak’ (Octreotide on a drip) prior to the surgery on 9th November 2010.
As is normal for such procedures, I had therisksexplained to me. There seemed to be a lot of risks on the list and my surgeon, Mr Neil Pearce, carefully explained each one. Death was on the list but I was happy to hear he had a 100% record on his ‘table’. Trust is an extremely important word when you’re in this situation.
As a snub to cancer, I refused the offer of a wheelchair and chose to walk to the operating theatre at around 2.30pm. So together with my ‘drip fed’ Octreotide trolley and wearing my surgical stockings and gown (carefully fastened at the rear!), I wandered down to the operating theatre with my escorting nurse.
The 9-hour operation was designed to debulk what was described as “extensive intra-abdominal neuroendocrine disease”. The operation comprised the removal of 3 feet of small intestine at the terminal ileum plus a right hemicolectomy, a mesenteric root dissection taking out the nodes on the superior mesenteric artery and a mesenteric vein reconstruction. With the assistance of a vascular surgeon, my NET surgeon also dissected out a dense fibrotic retro-peritoneal reaction which had encircled my aorta and cava below the level of the superior mesenteric artery. Phew! Thank goodness I was asleep 🙂
In those days, I had no idea that 10th November was NET Cancer Day. Some 8 years later I not only celebrate the fact that I woke up on this date after my first major surgery but that I have also woken up to the idea and inspiration behind NET Cancer Day in terms of an awareness window of opportunity.
However, on the basis that you can never have enough awareness windows, for me EVERY DAY IS NET CANCER DAY and via my own social media channels, I’m making sure everyone knows!
Thanks for listening
Ronny
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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 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), (see below for more detail). It’s also possible to see predominantly serotonin secreting tumors in places such as the pancreas (although what you would call that type of NET is open for debate).
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.
Gastric (Stomach) NETs. Gastrin is the main hormone but there can also be histamine producing an atypical carcinoid syndrome effect.
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).
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
Serotonin
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.
Tachykinins
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
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
Kallikrein is a potent vasodilator and may account for the flushing and increased intestinal mobility.
Prostaglandins
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
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
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).
Endocrine Organs
Thyroid Gland
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.
Pituitary Gland
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.
Adrenal Glands
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).
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.
Parathyroid
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:
Diarrhea.
Indigestion.
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).
Diarrhea.
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.
Fast heartbeat.
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.
Diarrhea.
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.
Facial flushing.
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.
Diarrhea.
Steatorrhea (very foul-smelling stool that floats).
Gallstones.
Yellowing of the skin and whites of the eyes.
Weight loss for no known reason.
Too much pancreatic polypeptide may cause:
belly pain.
an enlarged liver.
Testing hormones
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.
I was never diagnosed with Irritable Bowel Syndrome (IBS) but sometimes I feel like I now have it. I know many others feel the same way. But when I look at the alternatives, I can’t help thinking it’s a small price to pay given that one of them might be a slow degrading quality of life until shuffling off this mortal coil. If I had the choice again, I would still take the surgery.
OPINION. Nutritional issues are one of the biggest challenges affecting most Neuroendocrine Cancer patients. It is also a key factor in maintaining a decent quality of life and for most countries without adequate NET Specialist Dietitian support, it remains an unmet need. In this article, I’m discussing the use of probiotics to combat the potential issue of small intestine bacterial overgrowth (SIBO) in Neuroendocrine Tumours. 
