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I think most people have had a form of medical testing at some point in their life, i.e. the sampling and testing of blood, urine, saliva, stool or body tissue. In a nutshell, the medical staff are just measuring the content of a ‘substance’ and then taking a view whether this is normal or not based on pre-determined ranges. These tests are normally done as a physician’s reaction to symptom presentation or maintenance/surveillance of an existing diagnosed condition. Sometimes, abnormal results will lead to more specialist tests.
In cancer, these tests are frequently called ‘markers’. Most tumour markers are made by normal cells as well as by cancer cells; however, they are produced at much higher levels in cancerous conditions. These substances can be found in the blood, urine, stool, tumour tissue, or other tissues or bodily fluids of some patients with cancer. Most tumour markers are proteins. However, more recently, patterns of gene expression and changes to DNA have also begun to be used as tumour markers. Many different tumour markers have been characterized and are in clinical use. Some are associated with only one type of cancer, whereas others are associated with two or more cancer types. No “universal” tumour marker that can detect any type of cancer has been found.
There are some limitations to the use of tumor markers. Sometimes, noncancerous conditions can cause the levels of certain tumor markers to increase. In addition, not everyone with a particular type of cancer will have a higher level of a tumour marker associated with that cancer. Moreover, tumour markers have not been identified for every type of cancer. Tumour markers are not foolproof and other tests and checks are usually needed to learn more about a possible cancer or recurrence. Technically, a biopsy is a tumour marker but I’ll not be discussing that today. I more or less covered biopsies in my blog on NETs – Stages and Grades.
I’d also like to talk about certain other tests, in particular, hormone levels as these tests are really important to help determine the type of Neuroendocrine Tumour. NETs will sometimes oversecrete hormones and this can give clues to the type. The constraints mentioned above apply to hormone levels and other tests to a certain extent. The post will not cover routine blood tests (i.e. complete blood count etc) as although they may point to a problem, these tests do not necessarily indicate a particular type of NET.
Sequencing of marker testing – diagnosis
The sequencing of marker testing may have been different for many patients. In my own experience, I had a biopsy and then the biochemical checks were carried out. So regardless of the results of my marker tests, I was to be diagnosed with NETs. Those with lengthy and difficult diagnostic phases will perhaps have had a different sequence with the biochemical markers providing evidence for further tests to formally diagnose. Markers alone will normally not be enough for a diagnosis but they do, however, feed into the treatment plan and provide a baseline at diagnosis and for tracking going forward.
The use of markers tends to be different on an international basis, e.g. specific marker tests can be developed in-country by independent labs. Testing can also vary between in-country labs through the use of different commercially available ‘testing kits’. Moreover, the ‘normal’ test range can vary from hospital to hospital, even within the same tests. I can only imagine that clinical staff have their own versions of risk thresholds when dealing with test results. Even when results are just above or below, individual physicians can take their own view in a subjective manner. Testing is best done at the same lab each time if possible.
Here’s two tips I always give people: 1 – always get your results (preferably on paper) and track them yourself (I use a spreadsheet). 2 – When comparing results inside patient forums, always add the unit of measurement (i.e. g/L, mmol/L, umol/L etc etc). Failure to do this can at best confuse and at worst frighten patients. Compare apples with apples not with pears!
There are many markers involved with NETs. Some do different jobs and some are just variants measuring the same thing (more or less efficiently). You may also see something called ‘gold standard’ in reference to NET Tumour markers. Although thinking is changing (more on this below) and can vary from country to country, it is generally accepted that Chromogranin A and 5HIAA are the gold standard markers for tumour bulk and tumour functionality respectively. These gold standard tests may not be applicable to every type of NET, particularly 5HIAA. I’m also aware that US doctors are reducing the dependency on CgA and using Pancreastatin instead (although many are measuring both).
NETs are known to be heterogeneous in nature (i.e. consisting of or composed of dissimilar elements; not having a uniform quality throughout). Whilst some markers can be used widely, it follows that there are many very specialist marker tests for individual types of NET. I think this applies to 3 broad categories of NETs: Tumours known to potentially oversecrete Serotonin and and perhaps others (mainly midgut), Pancreatic NETs (or pNETs) secreting various hormones by type; and other less common types and/or syndromes which might be considered by some to be even more complex than the former two and in some cases there are big overlaps.
Another interesting thing about NET markers is that an undiagnosed patient may undergo several specialist tests to eliminate the many possibilities that are being presented as vague and common symptoms. Sometimes this is necessary to eliminate or ‘home in’ on a tumour type or syndrome/hormone involved (it’s that jigsaw thing again!).
Markers too can be divided into broad categories, those measuring how much tumour is in your body and its growth potential and those measuring how functional (or not) those tumours are. The latter can probably be expanded to measure/assess excess hormone secretion and syndromes.
Markers for measuring Tumour bulk or load/growth prediction
Chromogranin (plasma/blood test)
Chromogranin is an acidic protein released along with catecholamines from chromaffin cells and nerve terminals. This statement alone might explain why it is a good marker to use with NETs. Depending on the test kit being used, you may see test results for Chromogranin A (CgA) and Chromogranin B (CgB) – the inclusion of CgB tends to be confined to Europe. There is also mention of Chromogranin C (CgC) in places but I’ve never heard of this being used in conjunction with NETs.
One of the disadvantages of CgA is that the results can be skewed by those taking Proton Pump Inhibitors (PPIs). Many NET patients are taking PPIs to treat GERD (….and Zollinger-Ellison Syndrome). In the long-term, this has the result of increasing gastrin levels which can lead to an increase of CgA in the blood including for some months after discontinuing. CgB is said not be as influenced by the use of PPI as CgA. In addition to the issue with PPIs, CgA levels may also be elevated in other illnesses including severe hypertension and renal insufficiency. CgB is also said to be more sensitive to Pheochromocytoma.
Elevated CgA is a constant and somewhat excitable discussion point on patient forums and not just because of the lack of unit of measurement use I discussed above. Some people get quite excited about a single test result. I refer to Dr Woltering et al (ISI Book) where it clearly states that changes in CgA levels of more than 25% over baseline are considered significant and a trend in serial CgA levels over time has been proven to be a useful predictor of tumour growth (i.e. a single test result with an insignificant rise may not be important on its own). Dr Woltering also gives good advice on marker tests when he says “normal is normal” (i.e. an increased result which is still in range is normal).
Here is a nice graphic explaining what else could be the cause of elevated CgA:
CgA appears to be a widely used tumour marker and is effective in most NETs (foregut, midgut and hindgut). It is also sensitive to Pheochromocytoma, particularly when correlated with a 131I-MIBG scan. Interestingly Chromogranin can also be used in the immunohistochemical staining of NET biopsy samples (along with other methods).
As for my own experience, my CgA was only elevated at diagnosis, remained elevated after intestinal surgery but returned to normal after liver surgery (indicating the effect of liver tumour bulk on results). It also spiked out of range when some growth in a distant left axillary node was reported in Jan 2012. Following a lymphadenectomy, it returned to normal again and has remained in range to this day. It has been a good predictor of tumour bulk for me and I’m currently tested every 6 months.
In effect, this marker does the same job as CgA. Interestingly, Pancreastatin is actually a fragment of the CgA molecule. There have been many studies (mainly in the US) indicating this is a more efficient marker than CgA, and not only because it is not influenced by the use of PPI. It has also been suggested that it’s more sensitive than CgA and therefore capable of detecting early increases in tumour burden. It has also been suggested it can be an indication of tumour ‘activity’ (whatever that means). It is widely used in the US and some physicians will use it in preference to CgA (…..although from what I read, CgA also seems to be tested alongside). I’m starting to see this mentioned in the UK.
Neurokinin A (NKA)
This is not a well publicised test. However, it is something used in USA but I’d like to hear from others to validate its use elsewhere. In a nutshell, this test, which only applies to well differentiated midgut NETs, appears to have some prognostic indication. I discovered this test in the ISI NET Guidance and it’s backed up by a study authored by names such as Woltering, O’Dorisio, Vinik, et al. This is not a one-off test but one designed to be taken serially, i.e. a number of consecutive tests. These authors believe that NKA can also aid in the early identification of patients with more aggressive tumors, allowing for better clinical management of these patients. NKA is sometimes called Substance K.
Neuron-Specific Enolase (NSE)
In patients with suspected NET who have no clear elevations in the primary tumor markers used to diagnose these conditions, an elevated serum NSE level supports the clinical suspicion.
Markers for measuring Tumour functionality/hormone/peptide levels
So far, I’ve covered basic tumor markers which have a tumor bulk and/or prognostic indication. This section is a slightly more complex area and many more tests are involved. There’s often a correlation between CgA/Pancreastatin and these type of markers in many patients i.e. a serial high level of CgA might indicate a high level of tumour bulk and therefore increased production of a hormone in patients with a syndrome or oversecreting tumor. However, it frequently does not work out like that, particularly when dealing with non-functioning tumours.
The type of marker for this element of NET diagnosis and surveillance will vary depending on the type of NET and its location (to a certain extent). Like tumour bulk/growth, there might be different options or test variants on an international basis. There are too many to list here, so I’ll only cover the most common.
Serotonin Secreting Tumors
There are a few markers in use for measuring the functionality of this grouping of tumours. This tumour group has a tendency to secrete excess amounts of the hormone Serotonin although it differs depending on the area of the primary. For example, hindgut tumours tend to secret lower levels than foregut and midgut and therefore this test may present within range. Please also note there may be other hormones of note involved. The antiquated and misleading term ‘Carcinoid’ is sometimes used as a descriptor for these tumours and more and more NET scientific organisations and specialists are now avoiding use of this term.
5HIAA. 5HIAA is a metabolite of Serotonin thus why it’s a useful thing to measure to assess functionality in this grouping of tumours. 5HIAA is actually the ‘gold standard’ test for functioning serotonin secreting tumours. It’s a key measure of the effects of carcinoid syndrome and the risk of succumbing to carcinoid heart disease. However, there are two methods of testing: Urine and Plasma. The latter is mainly used in USA but other countries are now looking at implementing the plasma version (in fact I’m now tested in both at my local hospital in UK). The rather obvious key difference between the two is practicality. With the 24 hour urine, there are two key issues: 1. The logistics (i.e. lug the jug). 2. Fasting for up to 3 days prior to the test (4 if you count the day of the test). There are numerous variations on the fasting theme but most labs tend to say not to eat at least the following foods that contain high levels of serotonin producing amines: avocados, bananas, chocolate, kiwi fruit, pineapple, plums, tomatoes, and walnuts. Some lists contain additional items. With the plasma version, the fasting period is reduced to 8 hours. There are also medicinal limitations including drugs that can also alter 5-HIAA urine values, such as acetanilide, phenacetin, glyceryl guaiacolate (found in many cough syrups), methocarbamol, and reserpine. Drugs that can decrease urinary 5-HIAA levels include heparin, isoniazid, levodopa, monoamine oxidase inhibitors, methenamine, methyldopa, phenothiazines, and tricyclic antidepressants. Patients should talk to their doctor before decreasing or discontinuing any medications.
As for my own experience, my 5HIAA (urine) was elevated at diagnosis only returning to normal after removal of my primary and commencement of Lanreotide. It has been a good measure of tumour functionality for me and I’m currently tested every 6 months.
Other tests for the tumour subgroup include but not limited to:
Serum Serotonin (5-HydroxyTryptamine; 5-HT). Firstly let’s deconflict between 5HIAA above and the serotonin (5-HT) blood test. 5HIAA is a metabolite of serotonin but the serotonin test is a measure of pure serotonin in the blood. Morning specimens are preferred and this is a fasting test (10-12 hours). There is always debate on forums about Serum Serotonin results. I have Dr Liu on record as saying “a high serotonin level measured in the blood in isolation really isn’t that dangerous. It’s the 5HIAA (a breakdown product of serotonin, which is easily measured in the blood and urine) that is considered to be more indicative of persistent elevated hormone. It’s this test that is most closely related to the carcinoid heart disease”.
Histamines – Usually associated with foregut tumors. Appears to be involved in patchy rashes and flushing. The advice in the ISI NET book is no anti-histamine medication to be taken for 48 hours prior to blood draw.
Gastric NETs (Stomach)
Testing will be different depending on the Type:
- Type 1 – Typical Low Grade, tends to be caused by atrophic gastritis.
- Type 2 – Atypical Intermediate Grade and tends to be caused by gastrin secreting tumours. Type 2 normally needs a check for MEN1/Zollinger-Ellison Syndrome.
- Type 3 – Tend to be larger and more aggressive tumours.
The key makers are CgA and Gastrin although Gastrin may not be elevated in Type 3. Gastrin ph is useful to differentiate between Type 1 and Type 2. 5HIAA can be considered but Carcinoid Syndrome is rare in Gastric NETs.
NETs of the Pancreas (pNETs)
pNETs can be very difficult to diagnose and not only because they share some presentational similarities to their exocrine counterparts. Some pNETs actually comprise tumours arising in the upper part of the duodenum (small intestine) close to the Pancreas. Moreover, more than half of pNETs are non-functional which increases the difficulty in suspecting and then finding the tumours. However, where there is clinical presentation or suspicion, these symptoms can lead to the appropriate testing to support the output of scans. The fasting gut profile mentioned above can be useful in identifying the offending hormones when the type of NET is not yet known.
Gut Hormones (Glucagon, Gastrin, VIP, Somatostatin, Pancreatic Polypeptide)
A gut hormone screen is used for the diagnosis of a variety of endocrine tumours of the pancreas area. Analysis includes gastrin, VIP, somatostatin, pancreatic polypeptide, and glucagon, but there may be others depending on processes used by your ordering specialist or hospital.
1. You may see this referred to as a ‘Fasting Gut Profile’ or a ‘Fasting Gut Hormone Profile’.
2. The individual hormones measured seem to differ between hospital labs.
3. The fasting conditions also vary between hospitals and labs but all agree the conditions are critical to the most accurate results. Always ask for instructions if you’re offered this test.
The gastrin test is usually requested to help detect high levels of gastrin and stomach acid. It is used to help diagnose gastrin-producing tumours called gastrinomas, Zollinger-Ellison (ZE) syndrome, and hyperplasia of G-cells, specialised cells in the stomach that produce gastrin. It may be measured to screen for the presence of multiple endocrine neoplasia type I (MEN) It may be used if a person has abdominal pain, diarrhoea, and recurrent peptic ulcers. A gastrin test may also be requested to look for recurrence of disease following surgical removal of a gastrinoma.
Vasoactive intestinal peptide (VIP) measurement is required for diagnosis of pancreatic tumour or a ganglioneuroma which secretes VIP. Administration of VIP to animals causes hyperglycaemia, inhibition of gastric acid, secretion of pancreatic bicarbonate and of small intestinal juice, and a lowering of systemic blood pressure with skin flush. These features are seen in patients with a tumour of this type which is secreting VIP.
Glucagon is measured for preoperative diagnosis of a glucagon-producing tumour of the pancreas in patients with diabetes and a characteristic skin rash (necrolytic migratory erythema).
Pancreatic polypeptide (PP) production is most commonly associated with tumours producing vasoactive intestinal polypeptide and with carcinoid syndrome and, less commonly, with insulinomas and gastrinomas.
When secreted by endocrine tumours, somatostatin appears to produce symptoms similar to those seen on pharmacological administration, i.e. steatorrhoea, diabetes mellitus and gall stones.
There are several types of pNETs, each with their own syndrome or hormone issue. When they are suspected due to the presentational symptoms, the markers that could be used are listed below. These types of tumours are complex and can be related to one or more syndromes. A patient may be tested using multiple markers to include or exclude these. Depending on other factors, some physicians may recommend additional marker testing in addition to the most common types below.
Insulinoma – Insulin, Proinsulin, C-peptide
Gastrinoma– Gastrin, Gastrin pH
Glucagonoma – Glucagon, Insulin, Pancreatic Polypeptide (PP), Adrenocorticotropic hormone (ACTH)
VIPoma – Vasoactive Intestinal Polypeptide (VIP), Electrolytes (due to profuse diarrhea)
Somatostatinoma – Somatostatin (plasma somatostatin like immunoreactivity)
PPoma – Pancreatic Polypeptide (PP)
Pheochromocytoma/Paraganglioma – Adrenaline-producing tumours. Plasma and urine catecholamines, plasma free total metanephrines, urine total metanephrines, vanillylmandelic acid (VMA)
Medullary Thyroid Cancer – Calcitonin
Parathyroid– Parathyroid hormone (PTH), Serum Calcium
Pituitary/Cushings – Adrenocorticotropic hormone (ACTH), Cortisol
Multiple Endocrine Neoplasia (MEN). Please note MEN is a group of distinct syndrome not a tumor. Complex area and tends to be multiple instances of some of the tumours above. For a breakdown of MEN types and locations, check out my MEN blog ‘Running in the Family’
Carcinoid Heart Disease(CHD) (Hedinger syndrome) I’m not really talking directly about a tumour here but thought it would be useful to include a blood test called NT-proBNP. I’ve left a link to my CHD blog in the paragraph heading for those who wish to learn more about CHD in general. For those not offered an annual Echocardiogram or are ‘non-syndromic’ there is a screening test that can give an indication of any heart issue which might then need further checks.
The Future – Molecular Markers?
This is testing using DNA and genes. Exiting but complex – check out this article which involved some NETs.
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— Ronny Allan (@RonnyAllan1) March 3, 2016
I’ve never really understood why people get upset or annoyed when someone tells them they look well. Maybe I just think differently than others? I like to look for the positive things these well-meaning messages can convey. Most people are just trying to be nice, even if it comes over clumsy. Personally, I love it when people tell me I look well, I mean who wants to look unwell? If I’m feeling mischievous, I sometimes say “yes….. but you should see my insides“. Most of the time, it dispels any awkwardness and they follow my laughter.
Yesterday, I listened to a few video clips of a very inspiring young lady who eloquently delivered her view of what it is like to have an invisible disease and still look the ‘perfect picture of health’. She did it in such a way that I could never do and I guess she feels the same way about looking well on the surface. This is a lady who has a very rare disease and struggles with enormous amounts of pain. However, you wouldn’t think it to look at her. I think her messages are really worth listening to.
If you can’t see an illness, is an illness really there?
— Stanford Medicine X (@StanfordMedX) September 17, 2016
My invisible disease allows me to look the picture of perfect health.
— Stanford Medicine X (@StanfordMedX) September 17, 2016
What an inspiration! Thanks Danielle.
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It’s amazing to think that one minute I’m back from a holiday in the Caribbean and the next minute I’m being told the inside of my body is a ‘train crash’. Just how does that work? In July 2010, I said to the Gastroenterologist investigating my low hemoglobin “I’m not even feeling ill”. He sent me to an Oncologist who then told me that without treatment, the prognosis wasn’t good (i.e. I would eventually die). I also told him I wasn’t feeling ill ….as if my protest was somehow going to reverse the situation!
- 20 months prior I had a colonoscopy after a short-term change of stool colour. Nothing found.
- I also had some very infrequent bouts of diarrhea – I don’t normally get diarrhea so it must be something I’d eaten……… I carried on.
- I started experiencing ‘flushing’ sensations (hot but dry) some 6-9 months prior to diagnosis – Despite this being very strange, I kept this to myself and ……..I carried on.
- I was exhausted – I blamed it on my appetite for work……..I carried on.
Boy, am I now in tune with my body! If you think something is wrong and it just isn’t normal, follow your gut instinct, see someone, see that someone again and then see someone else if necessary. Keep a detailed diary of your symptoms, do your homework and let the medical practitioner know everything. This is the least you can do. This is also extremely relevant after diagnosis.
Doctors don’t have a cure for your “stiff upper lip”, there is no prescription. Only YOU can take action. Now go see that doctor or at least talk to someone.
Procrastination, aided and abetted by your ‘stiff upper lip’ – it’s a killer.
You may also enjoy my blog Poker Face or Cancer Card
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— Ronny Allan (@RonnyAllan1) March 3, 2016
Diarrhea can be a symptom of many conditions but it is particularly key in Neuroendocrine Tumour (NET) Syndromes and types, in particular, Carcinoid Syndrome but also in those associated with various other NET types such as VIPoma, PPoma, Gastrinoma, Somatostatinoma, Medullary Thyroid Carcinoma.
Secondly, it can be a key consequence (side effect) of the treatment for Neuroendocrine Tumours and Carcinomas, in particular following surgery where various bits of the gastrointestinal tract are excised to remove and/or debulk tumour load.
There are other reasons that might be causing or contributing, including (but not limited to) endocrine problems such as hyperthryoidism, mastocytosis or Addison’s disease (which may be secondary illnesses in those with NETs). It’s also possible that ‘non-sydromic’ issues such as stress and diet are contributing. It could be caused by other things such as Irritable Bowel Syndrome (IBS). Yes, believe it or not, NET Patients can get normal diarrhea causing diseases too!
I want to give a general definition of diarrhea as there are many variants out there. In general, they all tend to agree that diarrhea is having more frequent, loose and watery stools. Three or more stools per day seems to be the generally accepted threshold, although some sites don’t put a figure on it. It’s not pleasant and just about everyone on the planet will suffer it at some point in their life, perhaps with repeated episodes. Normally it’s related to some kind of bug, or something you’ve eaten and will only last a few days before it settles (acute diarrhea). Diarrhea lasting more than a couple of weeks is considered chronic and some people will require medical care to treat it. It can also be caused by anxiety, a food allergy/intolerance or as a side effect of medicine. Pharmacists and GPs will be seeing many patients with this common ailment every single day of business.
Diarrhea induced by a Syndrome
When you consider the explanation above, it’s not really surprising that diarrhea related symptoms can delay a diagnosis of Neuroendocrine Cancer (and most likely other cancers too, e.g. pancreatic cancer, bowel cancer). For example, diarrhea is the second most common symptom of Carcinoid Syndrome (Flushing is actually the most common) and is caused mainly by the oversecretion of the hormone Serotonin from the tumours. Please note diarrhea from other types of syndromes or NETs may be caused by other hormones. I’ve heard stories of people being told they have IBS or something similar for years before they received what is now a late diagnosis and at an advanced cancer stage. This is only one of the reasons why NETs is not an easy condition to diagnose, although it is possible that some people actually had IBS and it was masking the NET. Even after treatment to remove or reduce tumours, many people will remain syndromic and need assistance and treatment to combat diarrhea induced by a NET syndrome (see below).
Diarrhea as a Consequence (Side effect) of Neuroendocrine Cancer Treatment
All cancer treatments can have consequences and Neuroendocrine Cancer is definitely no exception here. For example, if they chop out several feet of small intestine, a chunk of your large intestine, chunks (or all) of your stomach or your pancreas, your gallbladder and bits of your liver, this is going to have an effect on the efficiency of your ‘waste disposal system’. One effect is that it will now work faster! Another is that the less effective ‘plumbing’ may not be as efficient as it was before. There are also knock-on effects which may create additional issues with the digestive system including but not limited to; Malabsorption and SIBO. I recommend you read my posts on Malabsorption and SIBO.
Surgery can often be the root cause of diarrhea. A shorter gut for example, means shorter transit times presenting as increased frequency of bowel movements. Another example is the lack of terminal ileum can induce Bile Acids Malabsorption (BAM) (sometimes known as Bile Salts Malabsorption) in degrees of severity based on size of resection. Lack of a gallbladder (common with NETs) can also complicate. Bile Acids are produced in the liver and have major roles in the absorption of lipids in the small intestine. Following a terminal ileum resection which includes a right hemicolectomy, there is a risk that excess Bile Acids will leak into the large intestine (colon) via the anastomosis (the new joint between small and large intestines). This leakage can lead to increased motility, shortening the colonic transit time, and so producing watery diarrhea (or exacerbating an existing condition). Although this condition can be treated using bile acid sequestrants (i.e. Questran), it can be difficult to pinpoint it as the cause.
Surgery of the pancreas can also produce effects such as exocrine pancreatic insufficiency which can lead to a malabsorption condition known as steatorrhea which may be confused with diarrhea (although some texts call it a type of diarrhea). It isn’t really diarrhea but it may look like it given the presentation of the faeces and patients may suffer both diarrhea and steatorrhea concurrently. Patients will recognise it in their stools which may be floating, foul-smelling, greasy (oily) and frothy looking. Treatment options will mainly include the use of Pancreatic Enzyme Replacement Therapy or PERT for short (Creon etc).
Many non-surgical treatments can also cause diarrhea, including but not limited to; somatostatin analogues (see below), chemotherapy, biological targeted therapy (e.g. Everolimus, Sunitinib), radiotherapy.
Somatostatin analogues are an interesting one as they are designed to inhibit secretion of particular hormones and peptides by binding to the receptors found on Neuroendocrine tumour cells. This has the knock-on effect of inhibiting digestive/pancreatic enzymes which are necessary to break down the fat in our foods leading to Malabsorption of important nutrients. This may worsen the steatorrhea in pancreatic NET patients but also lead to steatorrhea in others with non-pancreatic locations who have been prescribed these drugs.
Clearly, I cannot offer any professional medical advice on coping with diarrhea, I can only discuss my own situation and what I found worked for me. Don’t forget, like many diseases, what works for one, might not work for another. However, I did tackle my problems following the advice of an experienced dietitian who specialises in NET Cancer. That said, I was ‘sleep walking’ for over 2 years thinking my issues were just part of the way things were after my treatment. I was wrong about that!
Treatment for Syndrome Induced Diarrhea
Like many other NET patients, I’m on a 28 day injection of somatostatin analogues (in my case Lanreotide). Both Octreotide and Lanreotide are designed to reduce the effects of NET syndromes and therefore can often make a difference to syndrome induced diarrhea. These drugs also have anti-tumour effect and so even if you are not syndromic or they do not halt or adequately control syndrome induced diarrhea, they are still a valuable contribution to NET treatment.
Some syndromic patients find they still have diarrhea despite somatostatin analogues and they end up having ‘rescue shots’ or pumps for relief (both of these methods tend to be Octreotide based). (Hopefully they are not getting confused between diarrhea caused by the non-syndrome effects – see above). Some have more frequent injections of the long acting versions of somatostatin analogues which has the effect of increasing the dosage. There’s a new drug available for those whose carcinoid syndrome induced diarrhea is not adequately controlled or perhaps they are unable to have somatostatin analogues as a treatment. Telotristat Ethyl works by inhibiting tryptophan hydroxylase (TPH), a chemical reactor involved in the manufacture of serotonin, which is the main cause of syndrome induced diarrhea. It was approved by the US FDA in February 2017, EU areas in September 2017, and is on the way to being approved elsewhere. Read about this drug here.
Sorting out the symptoms – post diagnosis
I like to describe this as the Neuroendocrine Cancer jigsaw. It’s a really difficult one and sometimes you cannot find a piece, or the pieces won’t fit. However, metaphorically speaking, the missing piece might be a NET specialist presentation, a comment, statement or view from another patient, a link to an article from a reputable source, or even something you do to improve your lot – there might even be trial and error involved. It might even be this blog post!
How do you work out whether diarrhea is caused by a hormone producing tumour or by the side effects of treatments? There’s no easy answer to this as both might be contributing. One crude but logical way is to just accept that if you have normal hormone markers, for example 5HIAA (there could be more for other tumour/syndrome types), and you’re not really experiencing any of the other classic symptoms, then your syndrome might be under control due to your treatment (e.g. debulking surgery and/or somatostatin analogues, or another drug). My Oncologist labels me as ‘non-syndromic’ – something which I agree with. I’m 99.999999% sure my issues are as a result of the treatment I’ve had and am receiving.
This disease is so individual and there are many factors involved including the type of syndrome/NET, patient comorbidities and secondary illnesses, consequences of the surgery or treatments performed, side effects of drugs – all of which is intermingled with suspicion and coincidence – it’s that jigsaw again! I always like to look in more detail to understand why certain things might be better than others, I always challenge the ‘status quo’ looking to find a better ‘normal’. I really do think there are different strategies for syndrome induced diarrhea and that which is a result of treatment or a side effect of treatment. There’s also different prices, with inhibitors costing thousands, whilst classic anti-diarrhea treatments are just a few pennies. Adjustments to diets are free!
When I was discharged from hospital after the removal of my small intestinal primary, I was in the toilet A LOT (I was actually in the toilet a lot before I was discharged – check out my primary surgery blogs here) . My surgeon did say it would take months to get back to ‘normal’ – he was right and it did eventually settle – although my new ‘toilet normal’ was soft and loose and several times daily. My previously elevated CgA and 5HIAA were eventually back to normal and my flushing had disappeared. I didn’t have too many issues with diarrhea before diagnosis. Deduction: my issues are most likely not syndrome induced.
I read that many people find basic ‘Loperamide’ (Imodium) helps and I tend to agree with that if you are non syndromic and just need that little bit of help. I decided long time ago I would not become ‘hooked’ and only really take it for two purposes: 1) if I have a bad patch and 2) if I’m going on a long journey (i.e. on a plane perhaps). I estimate I’ve used 4 packets in as many years. Loperamide decreases the activity which causes intestinal motility (peristalsis). This has the effect of increasing the time material stays in the intestine therefore allowing more water to be absorbed from the fecal matter. Ideal for those with a shorter bowel due to surgery and advice from a medical professional is always advisable. To reduce the risk of malabsorption induced diarrhea and steatorrhoea, both of which can lead to loss of valuable nutrients, the use of Pancreatic Enzyme Replacement Therapy (PERT) might need to be introduced as required by your NET specialist.
As for my own strategy, I filtered out the advice from a NET specialist dietitian and have managed to make quite a difference to my Quality of Life (QoL) without resorting to really expensive drugs (which come with their own side effects). Here’s things that helped me:
- made some changes to diet (they were not huge changes),
- included supplementation where necessary,
- reduced stress as far as is practical to do,
- maintained a diary to help with monitoring progress or setbacks,
- hydration is also important (….still working on that one).
- started taking PERT (Creon) on 23 Dec 2017 (still assessing as at April 2018) but looks reasonably positive so far.
With no fancy and expensive drugs, I’ve gone from 6-8 visits to 1-2 visits (as a daily average, it’s actually 1.6). This didn’t happen overnight though, it took a lot of time and patience. All of this doesn’t mean to say I don’t have issues from time to time …… because I do!
In summary, I think it’s important that people be sure what is actually causing their diarrhea after diagnosis so that the right advice and the optimum treatment can be given.
Listen to Dr Wolin talking about this particular jigsaw puzzle – click here
Also see a nice article that come out of NANETS 2017 – click here
Of course, some people sometimes have the opposite effect but that’s in another blog here – Constipation
You may be interested in this development
Toilet cards are available from NET Patient Foundation – email firstname.lastname@example.org
You can also obtain a toilet card from Macmillan – see here
Thanks for reading
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Tweeps – have you retweeted this tweet? I won’t stop until I have 1000 retweets!
— Ronny Allan (@RonnyAllan1) March 3, 2016
You may remember that in 2016, I was nominated for 6 awards, got to the final for 2 (Blog and Community) and then won the Best in Show Community award. This is not only another great opportunity for me as a blogger and health activist but also a further opportunity for Neuroendocrine Cancer awareness. I do hope you will not only endorse me but also share with family and friends and recommend that they too endorse me. Only votes will get me to the final, after that it’s up to the judges and how much I can impress them in the lead up to the ‘red carpet’.
I’m pleased to inform you that I’m a nominee in 3 categories in the 2017 Annual WEGO Health Activist Awards.
1. Blog. This is the one I’d like to win most but the competition is pretty tough! I managed the final last year (shortlist of 5).
2. Patient Hero. That’s a very humbling award, ‘hero’ is a strong word in my vocab. I’m honoured to have been nominated.
3. Lifetime Achievement. Ditto as above but please note I’m only getting started!
Endorsing me is pretty easy although there may be some slight differences if using a desktop computer, a table or mobile phone:
You will be able to see the drop down for all 3 nominations (i.e. See picture below). It defaults to ‘Best in Show: blog’ and this is the one I would like most people to vote for. Complete the rest of the text (don’t worry about being contacted by WEGO, they don’t send out too much and you can always unsubscribe). There is an intermediate step where you can opt to share your endorsement on your own social media. I’ll leave it to you do opt to do this or not. You don’t need to create a WEGO account. If you opt not so share, press the back key or just close this window and then change the drop down for another award and it will already have retained your name and email. If you get lost, press the picture above and then select the right drop down. Press ‘Submit‘ for each award. After the first endorsements, the system should retain your details if you wish to endorse me for other awards. If you’re nominating me for more than one, it’s therefore nice and quick.
If anyone has technical difficulties with completing the endorsement, please let me know and I’ll try to help.
I do hope you will support me in this venture. Remember, an endorsement for me is an endorsement for Neuroendocrine Cancer awareness.
thanks – remember I cannot hope to win any of these awards without your votes so please share widely, please share for Neuroendocrine Cancer awareness.
Nominations are still open, so it’s not too late to add further nominations to the list – you can do this by clicking here.
I’m also active on Facebook. Like my page for even more news.
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 NET 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 just adds 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.
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.
While serotonin cannot cross the blood-brain barrier, tryptophan can, and almost all of it is converted to 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 and nutrition Blog 4).
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).
TPH is actually very interesting as this is how Telotristat Ethyl (XERMELO) is able to help with the symptoms of Carcinoid Syndrome diarrhea which is 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 – very exciting.
Serotonin and the Brain
There is constant discussion and assumption that serotonin-producing tumours are somehow causing depression, anxiety and rage. If you think about the role of serotonin, to my simple way of thinking, there doesn’t appear to be any concrete evidence to back up this suspicion. 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.
I know many people with cancer who suffer from depression, anxiety and rage but they do not 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. Serotonin is a natural substance found in the body and not just there to service NETs. If you didn’t have any, you wouldn’t be able to get out of bed according to one of my ‘favs’ Dr Gene Woltering.
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 is that low levels of tryptophan in the brain might be contributing to low levels of serotonin in the brain.
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, it would not majorly influence the result. 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 blog. 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.
I did say it was a difficult jigsaw!
Thanks for reading
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Tweeps – have you retweeted this tweet?
— Ronny Allan (@RonnyAllan1) March 3, 2016