It’s been 5 years since I saw a scalpel (….but my surgeon is still on speed dial)

im-still-here

5 years ago today, I had a bunch of lymph nodes removed. Two separate areas were resected, only one was showing growth but both were showing up as hotspots on an Octreoscan.  I had known since shortly after diagnosis in 2010 that ‘hotspots’ were showing in my left ‘axillary’ lymph nodes (armpit) and my left ‘supraclavicular fossa’ (SCF) lymph nodes (clavicle area). Some 10 months previously, I had a major liver resection and 5 months prior to the liver resection, I had a small intestinal primary removed including work on some associated complications.  There had always been a plan to optimise cytoreduction of my distant metastases, it was just a matter of timing. I still can’t get my head round why metastases from a small intestinal NET managed to get to this area but not others!

Distant nodal metastasis treatment

A total of 9 nodes were removed from my left armpit (a very common operation for breast cancer patients). The surgeon had inspected the area and found some were palpable and my normally stable Chromogranin A marker was showing a small spike out of range.  During the same operation under general anaesthetic, an ultrasound directed SCF nodal ‘exploration’ was carried out.  When biopsied, 5 of the 9 resected axillary nodes were tested positive (Ki-67 <5) but the 5 SCF nodes removed were tested negative. The subsequent Octreoscan still lit up in the left SCF area but the lights on the left axillary area were ‘extinguished’. There is no pathological enlargement or pain in the left SCF area – so this is just monitored.

Side effects

Apart from a very faint scar in the left SCF area, there does not appear to be any side effects from this exploratory surgery.  The left axillary area cut is well hidden by hair growth but I do sense a lack of feeling in the area.  Additionally, I have a very mild case of lymphedema in my left hand which occasionally looks slightly swollen – the consequences of cancer and its treatment.  Fluid build-up, or post-operative seroma, can be a side effect of a lymphadenectomy.  In fact, within a month of the operation, I had to have circa 160mls of fluid removed on 4 occasions from my armpit.  It was uncomfortable and painful, resulting in additional time off work.  The surgeon used a fine needle aspiration to draw out the fluid, a painless procedure. It eventually cleared up and everything was back to normal.  The specialist said my left arm would be slightly more susceptible to infections and suggested to avoid using my left arm for blood draws and other invasive procedures and injuries.

Other close calls (“to cut or not to cut”)

I have a 19mm thyroid lesion which was pointed out to me in 2013. This has been biopsied with inconclusive results.  Although the thyroid is an endocrine gland, it looks like a non-NET problem so far. Thyroid nodules are in fact very common and statistically, 50-70% of all 50-70 year olds will have at least one nodule present (i.e. if you are in your 50s, there is a 50% chance you will have one nodule and so on). The vast majority will never bother a person while they live.  I attend an annual Endocrine MDT where this is monitored in close coordination with the NET MDT. It’s actually managed by the same surgeon who carried out the nodal work above.

I have a 3mm lung nodule, discovered in 2011. Apparently, lung nodules are a pretty common incidental finding with 1 per 500 X-rays and 1 per 100 CT scans finding them.  This is monitored and hasn’t changed since noted.

You may also be interested in my post “Neuroendocrine Cancer – to cut or not to cut”

I watch and wait but I also watch and learn.  Make sure you are under some form of surveillance.

Thanks for reading

Ronny Allan

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Neuroendocrine Cancer – tumour markers and hormone levels

tumour-markers-molecular

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

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

markers

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

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

What this article will not cover

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

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

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

Sequencing of marker testing – diagnosis

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

Interpreting test results – International/National/Regional differences

The use of markers tends to be different on an international basis, e.g. specific marker tests can be developed in-country by independent labs. Testing can also vary in the same country as labs through the use of different commercially available ‘testing kits’.

Reference ranges are dependent on many factors, including patient age, gender, sample population, and test method, and numeric test results can have different meanings in different laboratories. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

Moreover, the ‘normal’ test range can vary from hospital to hospital, even within the same tests. I 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.

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

Here’s some tips I always give people:

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

2 – When comparing results inside patient forums, always add the range and if possible, the unit of measurement (i.e. g/L, mmol/L, umol/L etc etc).  Failure to do this can at best confuse, and at worst frighten patients.  Compare apples with apples not with pears!

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

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

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

NET Markers

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

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

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

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

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

The Anatomy

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

foregut midgut hindgut

Markers for measuring Tumour bulk or load/growth prediction

Chromogranin (plasma/blood test)

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

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

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

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

causes-of-cga-elevated

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

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

Pancreastatin

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

Neurokinin A (NKA)

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

Neuron-Specific Enolase (NSE)

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

Markers for measuring Tumour functionality/hormone/peptide levels

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

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

Serotonin Secreting Tumors

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

lug-the-jug
Lug the Jug

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

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

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

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

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

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

Gastric NETs (Stomach)

Testing will be different depending on the Type:

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

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

NETs of the Pancreas (pNETs)

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

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

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

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

Notes:

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

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

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

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

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

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

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

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

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

Insulinoma – Insulin, Proinsulin, C-peptide

Gastrinoma– Gastrin, Gastrin pH

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

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

Somatostatinoma – Somatostatin (plasma somatostatin like immunoreactivity)

PPoma – Pancreatic Polypeptide (PP)

Other NETs/Syndromes

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

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

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

Parathyroid– Parathyroid hormone (PTH), Serum Calcium.  Parathyroid hormone (PTH) is secreted from four parathyroid glands, which are small glands in the neck, located behind the thyroid gland. Parathyroid hormone regulates calcium levels in the blood, largely by increasing the levels when they are too low.  A primary problem in the parathyroid glands, producing too much parathyroid hormone causes raised calcium levels in the blood (hypercalcaemia – primary hyperparathyroidism). You may also be offered an additional test called Parathyroid Hormone-Related Peptide (PTHrP). They would probably also measure Serum Calcium in combination with these type of tests. The parathyroid is one of the ‘3 p’ locations often connected to Multiple Endocrine Neoplasia – MEN 1 – see MEN below.

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

HPA AXIS – It’s important to note something called the HPA axis when discussing pituitary hormones as there is a natural and important connection and rhythm between the Hypothalamus, Pituitary and the Adrenal glands.

Adrenocorticotropic hormone (ACTH) is made in the corticotroph cells of the anterior pituitary gland. It’s production is stimulated by receiving corticotrophin releasing hormone (CRH) from the Hypothalamus. ACTH is secreted in several intermittent pulses during the day into the bloodstream and transported around the body. Like cortisol (see below), levels of ACTH are generally high in the morning when we wake up and fall throughout the day. This is called a diurnal rhythm. Once ACTH reaches the adrenal glands, it binds on to receptors causing the adrenal glands to secrete more cortisol, resulting in higher levels of cortisol in the blood. It also increases production of the chemical compounds that trigger an increase in other hormones such as adrenaline and noradrenaline. If too much is released, The effects of too much ACTH are mainly due to the increase in cortisol levels which result. Higher than normal levels of ACTH may be due to:

Cushing’s disease – this is the most common cause of increased ACTH. It is caused by a tumor in the pituitary gland (PitNET), which produces excess amounts of ACTH. (Please note, Cushing’s disease is just one of the numerous causes of Cushing’s syndrome). It is likely that a Cortisol test will also be ordered if Cushing’s is suspected.

Cortisol

This is a steroid hormone, one of the glucocorticoids, made in the cortex of the adrenal glands and then released into the blood, which transports it all round the body. Almost every cell contains receptors for cortisol and so cortisol can have lots of different actions depending on which sort of cells it is acting upon. These effects include controlling the body’s blood sugar levels and thus regulating metabolism acting as an anti-inflammatory, influencing memory formation, controlling salt and water balance, influencing blood pressure. Blood levels of cortisol vary dramatically, but generally are high in the morning when we wake up, and then fall throughout the day. This is called a diurnal rhythm. In people who work at night, this pattern is reversed, so the timing of cortisol release is clearly linked to daily activity patterns. In addition, in response to stress, extra cortisol is released to help the body to respond appropriately. Too much cortisol over a prolonged period of time can lead to Cushing’s syndrome.  Cortisol oversecretion can be associated with Adrenal Cortical Carcinoma (ACC) which can sometimes be grouped within the NET family.

Other hormones related to ACC include:

Androgens (e.g. Testosterone) – increased facial and body hair, particularly females. Deepened voice in females.

Estrogen – early signs of puberty in children, enlarged breast tissue in males.

Aldosterone – weight gain, high blood pressure.

Adrenal Insufficiency (Addison’s Disease) occurs when the adrenal glands do not produce enough of the hormone cortisol and in some cases, the hormone aldosterone. For this reason, the disease is sometimes called chronic adrenal insufficiency, or hypocortisolism.

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

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

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

The Future – Molecular Markers?

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

Tumour Markers and Hormone levels – complex subject!

Thanks for reading

Ronny

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

 

Serotonin – the NET effect

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 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).

Are you happy with your serotonin?

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.  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.

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 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 as outlined above, 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, 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.

Summary

I did say it was a difficult jigsaw!

Thanks for reading

Ronny

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Neuroendocrine Cancer – it can be ‘smoke and mirrors’

Neuroendocrine Cancer smoke and mirrorsIn a previous life, I used the term ‘smoke and mirrors’ quite a bit.  I was used to dealing with many different types of people, some who wanted something, some who wanted to buy or sell something. Most of the time it was overt but the devil was usually in the detail.  Sometimes there was an element of ‘covertness’ or a ‘hidden agenda’.  It was always tricky working out the details of the hidden agenda and sometimes it was only known when it was too late.  Some of you will already be seeing where I’m going with this line of thinking – if so, you worked out my hidden agenda!

‘Smoke and Mirrors’ is basically a term connected to the art of deception, a con trick, a way in through confusion and trickery (think magicians on TV!). 

Whilst certain cancers can appear with precise symptoms and leave you under no illusion what you’re facing, others can be a bit more circumspect – Neuroendocrine Cancer can be one of those.  It will fool you into thinking you’re not even ill and even when it puts its head above the parapet, this can come over as a routine illness and/or vague symptoms which will deceive both you and your physicians.   Thus why awareness is really important.  I won’t repeat my key messages but you can find them here in my blog entitled “Neuroendocrine Cancer can be silent – but it doesn’t mean we should be” – the more these posts and ones like it are shared, the quicker we can discover the hidden agenda. 

I have another hidden agenda!  I was inspired to write this post by my friend and blogger Shannon – she writes a blog called ‘A tale of two tumours’.  I really like this blog because there are no hidden agendas, what you see is what you get and she has catchy titles.  I also like Shannon because she has a great attitude despite the fact that she is probably still looking for the ‘hidden agenda’ or at least bits of it (then again perhaps we all are?).

Shannon has one of the uncommon variants of our disease, one of those tricky cases it would seem.  Her issues started some time ago and she was eventually diagnosed with Cushing’s Disease (see my Syndrome blog).  She has previous issues with pituitary, parathyroid and recently diagnosed with a Thymic NET.  She believes there is a potential connection with MEN1 (see my blog Running in the Family) but this is currently dismissed by her physicians.

There is potentially a new problem outlined in her latest blog which inspired me to write this post.  She has a very strange symptom in that she can smell smoke despite there not being any smoke and this happens in different locations.  Her latest blog is her story about this symptom and what happened next.  Excuse the language but I would be frustrated too!  Read the blog ‘Where there is smoke …..’ by ‘clicking here’.

I wish Shannon well and hope she gets some answers – no more tumours please.  You are a survivor!

Thanks for listening

Ronny

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Running in the Family – Multiple Endocrine Neoplasia (MEN)


CancerDNAMarkers__0327

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

Overview

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

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

MEN Types

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

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

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

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

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

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

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

Associated Issues

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

Further information

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

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

Complex area.

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

Thanks for reading

Ronny

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Neuroendocrine Cancer – a difficult jigsaw

NET Cancer Jigsaw

A couple of years ago, I received a request from a reader asking if I would write an article about all the symptoms experienced by a Neuroendocrine Cancer patient and how to sort out what is and what isn’t associated with NETs.

Although I chuckled and raised eyebrows at the request, inside I was genuinely humbled that someone thought I was capable of achieving this herculean task.  I actually gave it quite a bit of thought to the point of compiling a matrix of types of NET, main symptoms, cross-referenced with the symptoms of the most common reported comorbidities. After it started to look like it might be bigger than the Empire State Building, I came to the conclusion that it’s an almost impossible task for a wee Scottish guy with less common disease 🙂  I also started to suspect that even the world’s top NET experts had not accomplished it either.

Here’s a picture of my work to date:

Book of NETS
A book listing all the possibly symptoms of NETs (clearly I’m joking with you)

I have, however, dabbled in attempts to work out my own problems over the past few years. NETs can present with a ‘syndrome’ – a bunch of symptoms normally caused by excessive hormone secretion, some of which are particularly vague and can sometimes continue to cause issues after treatment and beyond – it’s a real witch’s brew of symptoms. They can also cause non-syndromic issues pertaining to treatment side effects and it must also be noted that even NET patients get regular illnesses which adds to the issues healthcare professionals and patients face in monitoring NETs.

In my article “Neuroendocrine Cancer Syndromes – early signs of a late diagnosis”, I focused on the key symptoms experienced pre-diagnosis and then discussed how you might go about sorting out the symptoms from main side effects post treatment (another regular conundrum for most).  On a similar subject, you might want to check out my 5 E’s blog for carcinoid syndrome. I also compiled an article about the source of flushing and diarrhea given there were many differential diagnoses and not just syndromes.

NETs vs Other Illnesses

Adding another jigsaw piece to the issues with cancer and side effects – common comorbidities (many of an endocrine nature) can arise simultaneously. Is it connected with NETs are just another illness to manage alongside?  All of these factors can make it really difficult to determine the source of the symptoms.  I’m always conscious that the majority of NET patients are in their 5th decade onward and at an age where things start to go wrong quite naturally due to ‘time’ and ‘wear and tear’.

Here’s one classic example of this problem, I can see many people on forums also have diabetes (an endocrine disease). In the United States alone, nearly 7 million people have undiagnosed diabetes, according to the American Diabetes Association.  I can also see from the news in UK, that this is becoming a much bigger deal too – a report published in Feb 2018 claims that diagnoses have doubled in 20 years.  I’ve used the diabetes link as an example, there will be many other very common factors at play, e.g. hypothyroidism an age and gender relation issue.  It is certainly possible that many of the problems people face might just be an as yet undiagnosed/underlying condition, unconnected with NETs. To quote the great Dr Eric Liu, “even NET Patients get regular illnesses”.  Working it out is rather difficult though. Sometimes pragmatism is required. 

Syndromes vs Side Effects of Treatment

On forums where most people have a diagnosis and are undergoing treatment, there is regular discussion and Q&As about the source of symptoms, i.e. are they a result of a functioning syndrome (i.e. a consequence of the cancer) or something else?  For example, some people complain they still have (so-called) carcinoid syndrome diarrhea after bowel surgery………that needs some careful thought and understanding before coming to what might just be the wrong conclusion, particularly if all tumour markers are normal.  I have lost count of the number of times someone has asked about a symptom on a forum and got 50 different answers. One of the reasons why forums can be good at frightening rather than frighteningly good.  Personally, I never compare myself to strangers on the internet. I just hope most people are using the forums as ‘sounding boards’ and are simultaneously addressing these very complex issues with their doctors when they are genuinely concerned.

I really feel for anyone who is going through a difficult diagnosis or has been diagnosed and then continues to have numerous problems after initial treatment.  I also have a little bit of sympathy for primary care medical staff on the basis this is just one of over 200 types of cancer, many of which have wide age groupings adding to the complexity and difficulty. Moreover, many of the symptoms experienced by NET patients on analysis look very similar to everyday illnesses and other ailments. And if that wasn’t demanding enough for doctors, many patients present with already established and diagnosed comorbidities (other illnesses) which add another level of complexity. These difficulties can then continue throughout treatment. It can be a real challenge and I’m sure even Doctors can be totally flummoxed on occasion by patient presentations.

Summary

It is extremely difficult to “sort out the symptoms” when faced with multiple locations/tumour sub-types, multiple treatments causing multiple side effects, multiple side effects causing multiple symptoms, multiple comorbidities with symptoms similar to cancer syndromes and treatment side effects (and vice versa).  This disease can be very individual and what happens to one might not happen to another. Although we hope doctors generally take a holistic view when treating NET patients, I have a view that sometimes focussing in on a particular symptom might occasionally be a more effective route (the bottom-up approach – pun not intended!).  When eating an elephant, take one bite at a time!  It’s useful to know about the range of tumor markers and hormone markers – read more here.

 

One thing I have learned  ……educate yourself to the best of your abilities.  This will help you to better advocate for yourself.  Improvements are possible.

Neuroendocrine Cancer is a very difficult jigsaw and you sometimes need to look very hard for the missing piece!  The ‘missing piece’ can be variable and very individual, i.e. a NET specialist, access to a particular treatment or even just more support or access to support information that works.

Thanks for reading

Ronny

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Neuroendocrine Cancer Nutrition Series Article 2 – Gastrointestinal Malabsorption

This is the second article in the Neuroendocrine Cancer Nutrition series. In  the first article, I focused on Vitamin and Mineral deficiency risks for patients and there is a big overlap with the subject of Gastrointestinal Malabsorption. Those who remember the content will have spotted the risks pertaining to the inability to absorb particular vitamins and minerals. This comes under the general heading of Malabsorption and in Neuroendocrine Cancer patients, this can be caused or exacerbated by one or more of a number of factors relating to their condition. It’s also worth pointing out that malabsorption issues can be caused by other reasons unrelated to NETs. Additionally, malabsorption and nutrient deficiency issues can form part of the presenting symptoms which eventually lead to a diagnosis of Neuroendocrine Cancer; e.g. in my own case, I was initially diagnosed with Iron Deficiency Anemia in association with some weight loss. Even after diagnosis, these issues still need to be carefully monitored as they can manifest as part of the consequences of having cancer and cancer treatment.

Malabsorption will present via several symptoms which may be similar to other issues (i.e. they could masquerade as, or appear to worsen the effect of a NET Syndrome). These symptoms may include (but are not limited to) tiredness/fatigue/lethargy, stomach cramps, diarrhea, steatorrhea (see below), weight loss. Some of these symptoms could be a direct result of nutrient deficiencies caused by the malabsorption.  Some patients (and perhaps physicians?) could mistake these for symptoms of Neuroendocrine disease including certain syndromes, perhaps leading to prescribing expensive and unnecessary drugs when a different (and cheaper) strategy might be better.

Crash Course……. We eat food, but our digestive system doesn’t absorb food, it absorbs nutrients.  Food has to be broken down from things like steak and broccoli into its nutrient pieces: amino acids (from proteins), fatty acids and cholesterol (from fats), and simple sugars (from carbohydrates), as well as vitamins, minerals, and a variety of other plant and animal compounds. Digestive enzymes, primarily produced in the pancreas and small intestine (they’re also made in saliva glands and the stomach), break down our food into nutrients so that our bodies can absorb them.  If we don’t have enough digestive enzymes, we can’t break down our food—which means even though we’re eating well, we aren’t absorbing all that good nutrition.

What is malabsorption?

The malabsorption associated with Neuroendocrine Cancer is most prevalent with the inability to digest fat properly which can lead to steatorrhea. Patients will recognise this in their stools. They may be floating, foul-smelling and greasy (oily) and frothy looking. Many patients confuse steatorrhea with diarrhea but technically it’s a different issue although both issues may present concurrently. Whilst we all need some fat in our diets (e.g. for energy), if a patient is not absorbing fat, it ends up being wasted in their stools and in addition to the steatorrhea, it can also potentially lead to (unwanted) weight loss and micronutrient deficiencies of the fat-soluble vitamins A, D, E and K. Certain water-soluble vitamins, particularly B3 and B12, are also at risk. Many NET Patients are prescribed a supplement of pancreatic enzymes to combat these issues – see Article 5 in this series – Pancreatic Enzyme Replacement Therapy (PERT).

What causes it with NET Patients?

Structural Changes (i.e. Surgery) 

This can play a very big part in malabsorption issues. For example, if a patient has undergone Pancreatic surgery, this will most likely effect the availability of pancreatic (digestive) enzymes needed to break down food. Many Small Intestine NET (SI NET) patients will suffer due to the removal of sections of their ileum, an area where absorption of water-soluble vitamins and other nutrients take place. In fact, the terminal ileum is really the only place where B12 is efficiently absorbed.  Low B12 is known to cause fatigue.  Some patients with Gastric tumours succumb to pernicious anemia with the most common cause being the loss of stomach cells that make intrinsic factor. Intrinsic factor helps the body absorb vitamin B12 in the intestine. Although a less common tumour location, jejunum surgery could result in loss of nutrients as this section of the small intestine is active in digestive processes. Malabsorption issues for SI NETs are an added complication to the issues caused by a shorter bowel (e.g. increased transit times), something which is regularly assumed to be the effects of one of the NET Syndromes (particularly diarrhea and fatigue), when in actual fact, it’s a simple consequence of cancer treatment and may need a different treatment regime.

Evidence of the problems being caused by the effects of small intestinal surgery can be found in a recently published Swedish study which you can read here: Click here. This particular study recommends supplementation of B12 and D3 for those affected.  If you’re having trouble getting your physician to monitor your vitamin levels, show them these studies. I get these vitamins checked annually.

The Gallbladder and Liver

The Gallbladder plays an important part in the digestive system – particularly in fat breakdown. The liver continually manufactures bile, which travels to the gallbladder where it is stored and concentrated. Bile helps to digest fat and the gallbladder automatically secretes a lot of bile into the small intestine after a fatty meal. However, when the gallbladder is removed, the storage of bile is no longer possible and to a certain extent, neither is the ‘on demand automation’. This results in the bile being constantly delivered/trickled into the small intestine making the digestion of fat less efficient. One of the key side effects of Somatostatin Analogues  (Octreotide and Lanreotide) is the formation of gall stones and many Neuroendocrine Cancer patients have their gallbladder removed to offset the risk of succumbing to these issues downstream. However, the removal of the gallbladder increases the risk of Bile Acid Malabsorption (BAM) as described below. Any issues with Bile Ducts can also have a similar effect.

The Liver has multiple functions including the production of bile as stated above. However, one of its key functions within the digestive system is to process the nutrients absorbed from the small intestine.  If this process is affected by disease, it can potentially worsen the issues outlined above.

Bile Acids Malabsorption

Another risk created by the lack of terminal ileum is Bile Acids Malabsorption (BAM) (sometimes known as Bile Salts Malabsorption and some texts described the resultant diarrhea as ‘Bile Acid Diarrhea”). 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).

Somatostatin Analogues

Somatostatin Analogues can also impact (or worsen) the ability to digest fat as they inhibit the production of pancreatic digestive enzymes (amongst other things). This is a well-known side effect of both Octreotide and Lanreotide. The levels of the fat-soluble vitamins (ADEK) and B vitamins such as B12, need to be monitored through testing and/or in reaction to symptoms of malabsorption.  If necessary these issues need to be offset with the use of supplements as directed by your dietician or doctor. Supplements are less affected by malabsorption of nutrients but their efficiency can be impacted by fast gut transit times (thus why testing is important).  The evidence and recommendations for malabsorption caused by somatostatin analogues is here: Click Here.  

Overlapping Areas

Deficiencies of these vitamins and certain minerals can lead to other conditions/comorbidities, some more serious than others. For a list of the vitamins and minerals most at risk for Neuroendocrine Cancer patients, have a read of my article which was co-authored by Tara Whyand – Vitamin and Mineral deficiency risks.

There is a third article in this series discussing a related issue with Neuroendocrine Cancer, particularly where gut surgery has been performed. You can link directly to this article here  – “Gut Health” – (Gut Health, Probiotics and Small Intestinal Bacterial Overgrowth (SIBO)).

The fourth article  looks at Amines and why they can cause food reactions or exacerbate syndromes.

Many people also confuse steatorrhea with diarrhea (although these issues can appear simultaneously), again leading to wrong conclusions about the causes and effects, and worryingly, the treatment required. Check out my diarrhea article – click here.

Article 5 in this series looks at how to combat malabsorption caused by pancreatic insufficiency – Pancreatic Enzyme Replacement Therapy (PERT).

My article ‘The Diarrhea Jigsaw’ is complementary to this nutrition series.

Summary

A common problem in patients and from what I see, many just assume this is part of their various syndromes leading to the wrong therapy or no therapy as it’s simply ignored. Again, I remain very grateful to Tara Whyand for some assistance.

This is a big and complex subject and I only intended to cover the basics.  Everyone is different and nothing in here should be accepted as medical advice for you or anyone you know.  If you need professional advice, you should speak to your doctor or registered dietitian.

Thanks for reading

Ronny

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Neuroendocrine Cancer Nutrition Series Article 1 – Vitamin and Mineral Challenges

Vitamins & minerals
Vitamins & minerals – the biggest QoL challenge for NET Patients?

Despite learning early on in my journey that nutrition was going to be a challenge, I sensed the initial focus of my treatment was on getting rid of as much tumour bulk as possible and then controlling (stabilising) the disease through monitoring and surveillance. Clearly I’m happy about that! However, it eventually became clear that the impact of this constant treatment/controlling, meant that some of the less obvious signs of nutrient deficiency were potentially being missed.

This is one of the key reasons I believe there is a gap in specialist follow on support for Neuroendocrine Cancer patients – at least in the UK. As I said in blog post ‘I may be stable but I still need support’, Neuroendocrine Cancer patients need specialist dietary and nutritional advice covering a much wider spectrum than most cancer patients. In this blog, I also suggested that there does not appear to be enough research into these issues leaving many patients working out their own strategies post diagnosis and treatment.  However, I was delighted to see a study published in 2016 indicating a recognition of this problem.  The paper (click here), which was sponsored by ENETS Centres of Excellence (CoE) in UK, concluded that “Given the frequency of patients identified at malnutrition risk using MUST (malnutrition universal screening tool) in our relatively large and diverse GEP-NET cohort and the clinical implications of detecting malnutrition early, we recommend routine use of malnutrition screening in all patients with GEP-NET, and particularly in patients who are treated with long-acting somatostatin analogues”.  This amplifies the advice Tara has given many NET Patients in UK that regular blood checks of key vitamins at risk, particularly B12 and the fat-soluble ADEK (see more on this below).  Even those patients with very healthy diets can still succumb to these issues. Looking at the vast number of forum posts on this subject, perhaps this is also a problem outside of UK?

This is not just about what foods to avoid or eat in moderation, this is also about:

a. receipt of post surgical/treatment advice,

b. early knowledge and countermeasures for the side effects of ongoing and long-term treatment,

c. the intelligent use of supplements where they are applicable,

d. how to combat, treat or offset malabsorption and nutrient deficiencies caused by the complexities of their cancer and any treatment given.  Check out Blog 2 in this series which specfically looks at Malabsorption.  

e. how to deconflict these side effects with those of the various syndromes which can sometimes accompany Neuroendocrine Cancer.

In early 2011, shortly after my first major surgery and commencement of my monthly somatostatin analogue – Lanreotide (Somatuline), I started to notice a number of issues developing. I carefully searched for clues and I could see that some of my issues pointed to side effects from treatment (both from surgery and somatostatin analogues) and potentially some vitamin and mineral deficiencies. I had already been taking an ‘over 50‘ multivitamin tablet for some time before I was diagnosed and assumed I was already covered. Having analysed the issues I was experiencing at the time, I was specifically targeting B12 and my initial test score was just in range (i.e borderline). Surprisingly my multivitamin B12 content was 400% RDA – yet my blood test was borderline. That might explain the fatigue!

I later attended a fantastic patient day where I was introduced to the UK’s solitary Neuroendocrine Cancer specialist dietician. This subject was a revelation for me and I was alerted to the possibility that other vitamins and minerals could be at risk due to a combination of surgery and/or treatment, in particular the fat soluble vitamins A, D, E, K. Following a hastily arranged series of blood tests, I found my Vitamin D was insufficient and this has now been resolved through additional supplementation and more effort to absorb it through conventional means (i.e. the sun!).

I’m now on top of this issue through learning, understanding and basically becoming my own advocate. Please note this is a massive subject and the amount of information on the internet can be overwhelming.  Additionally, it is not an exact science and not everything will apply to every person.  Personally I would stick to sites where the advice is given by a nutritionist/dietician who is also experienced with Neuroendocrine Cancer.

I’m thankful to Tara Whyand who is an Oncology Dietician specialising in Neuroendocrine Cancer at the Royal Free Hospital.  Her research, advice and raising of these issues at patient meetings has been invaluable. As the only specialist in the UK (that I know of), she gets a lot of queries!  If you’re on twitter, you can follow Tara here:

https://twitter.com/LadyNourish

Even though I’ve had to limit this post to vitamin and mineral issues, it’s still much larger than what I normally produce.  Consequently, I’m planning further blogs on associated and overlapping subjects.

In the meantime, I’m very grateful to Tara for the input below:

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NET Patients are at Risk of Deficiencies

Over the past few years I have become more aware of vitamin and mineral deficiencies in NET patients, and the impact these can have on health and quality of life. When the focus of NET treatment is on eradicating and controlling the disease, the impact on nutrition, apart from obvious weight loss, means less obvious signs of micronutrient deficiency can be missed. Below is a list of nutrients which are those most at risk of becoming low enough to cause problems. It is important that the treatment of these deficiencies is discussed with your NET team so they can prescribe suitable doses.

Minerals

Magnesium

Magnesium blood tests are an unreliable measurement and there is no way of accurately measuring body stores.

Magnesium is a vital mineral required for the function structure of the human body. Prevalence of low blood magnesium levels varies from 7% to 11% in hospital patients and clinical magnesium deficiency is frequently observed in conditions causing steatorrhoea or severe chronic diarrhoea, and the degree of magnesium depletion correlates with the severity of diarrhoea and stool fat content. Signs of deficiency include low energy, fatigue, weakness, PMS, menstrual cramps, hormonal imbalance, insomnia, bone mineral density loss, muscle tension, spasms, cramps, cardiac arrhythmia, headaches, anxiousness, nervousness and irritability. If you think you could be deficient you must ensure you consume enough magnesium (375mg per day).

Zinc

Zinc levels are best measured using a combination of blood serum and urinary excretion levels.

Zinc affects the human body through a large number of channels affecting not only cell division, protein synthesis and growth, but also gene expression and a variety of reproductive and immunologic functions. Zinc deficiency is common in undernourished patients. The absence of sufficient levels of zinc in the human body is associated with a large number of adverse health outcomes, including lower immunity, alopecia, tiredness and impaired wound healing. If you are at risk of deficiency make sure you consume enough zinc (10mg per day). If you are clinically deficient your diet must be supplemented.

Iron

Iron deficiency (hypoferremia) and clinical iron deficiency anaemia is easily measured with a simple blood test.

Iron is essential for the formation of haemoglobin in red blood cells which binds oxygen and transports it around the body. Iron is also an essential component in many enzyme reactions and has an important role in the immune system. In addition, it is required for normal energy metabolism and for the metabolism of drugs and foreign substances that need to be removed from the body. Lower iron levels are common in NET patients and there may be several causes of this. Poor iron intake, dietary iron absorption-regulating factors (e.g., vitamin C and copper) or iron distribution factors (e.g. vitamin A), are believed to be causes. Patients may also lose iron due to blood loss from the bowel in intestinal or rectal NETs or after surgery. It may also be possible that diarrhoea in NETs causes malabsorption of iron in the intestine too. Symptoms include tiredness, paleness, thinning hair, impaired immunity and feeling breathless. If you are at risk of having lower than normal iron levels you must consume enough iron (14mg per day). If you are clinically deficient your diet must be supplemented.

Copper

Diagnosis of copper deficiency is based on low serum levels of copper and ceruloplasmin, although these tests are not always reliable.

Copper is an essential trace mineral that is required for human health. This micronutrient is necessary for the proper growth, development, and maintenance of bone, connective tissue, brain, heart, and many other body organs. Copper is involved in the formation of red blood cells, the absorption and utilization of iron and the synthesis and release of life-sustaining proteins and enzymes. These enzymes in turn produce cellular energy and regulate nerve transmission, blood clotting, and oxygen transport. Copper stimulates the immune system to fight infections, to repair injured tissues, and to promote healing. Copper also has an antioxidant effect against oxidative stress.  Gastrointestinal surgery can lead to malabsorption of copper and other micronutrients. Long term malabsorption of food from the gastrointestinal tract can also lead to copper deficiency which puts many more NET patients at risk.  Symptoms of deficiency include neutropenia, impaired bone calcification, myelopathy, neuropathy, and hypochromic anemia not responsive to iron supplements. If you are at risk of lower than normal levels of copper you must consume enough (1mg per day). If you are clinically deficient your diet must be supplemented.

Selenium

Selenium levels are measured using plasma selenium blood tests.

Selenium is an essential micronutrient in humans and functions in many biochemical pathways. Proposed antioxidant pathways of selenium, include the repair and prevention of oxidative damage, alteration of metabolism of carcinogenic agents, regulation of immune response and repair of DNA damage. It works alongside vitamin E and selenium levels are often low during cancer and in patients on long-term intravenous nutrition.  Symptoms of deficiency include muscle pain and tenderness.  Everyone is required to have 55 µg a day and if you are clinically deficient your diet will need to be supplemented.

Water Soluble Vitamins

B1-Thiamine

Thiamine is not usually tested as diagnosis is based on symptoms and a trial of thiamine supplementation. If a doctor is unsure, they will measure erythrocyte transketolase activity and run a 24-hour urinary thiamine excretion.

Vitamin B1, or thiamine is an essential B vitamin which is required for the breakdown of sugars and amino acids. Absorption of thiamine is greatest in the jejunum and ileum, but it is it is inhibited by alcohol consumption and by folic acid deficiency. The most common cause of deficiency is alcoholism, although states causing malabsorption such as gastrointestinal surgery are also a factor. It may also be possible that diarrhoea causing malabsorption of nutrients from the intestines could put a patient at NET patient at risk of deficiency. Symptoms initially include fatigue, irritability, poor memory, sleep disturbances, anorexia, and abdominal discomfort. When more severe it involves hospitalisation due the effects on the nervous system and heart.

Patients who are at risk of deficiency must consume enough thiamine (1.1mg thiamine per day). Patients who are deficient must have their diet supplemented.

B3-Niacin

Niacin is not usually tested but may be useful to confirm diagnosis using urinary excretion of N 1 -methylnicotinamide (NMN).

Niacin also refers to both nicotinamide and nicotinic acid and is required as part of the way energy is produced by the body.  When carcinoid tumours produce hormones such as serotonin, these patients suffer from carcinoid syndrome. These are symptoms such as flushing, diarrhoea, wheezing and damage to heart valves (carcinoid heart disease). When the tumours make large amounts of serotonin, the amino acid, tryptophan, gets used up. When tryptophan stores are low it cannot be converted into the vitamin niacin, which may then cause deficiency. In a NET study, 28 per cent of patients with gastroenteropancreatic /carcinoid tumours and carcinoid syndrome were niacin deficient. Patients without carcinoid syndrome did not have niacin deficiency.  Niacin deficiency can also be caused by cirrhosis and diarrhea. Niacin deficiency leads to pellagra, the typical symptoms of which are diarrhea, dermatitis and dementia. All patients with carcinoid syndrome must take a nicotinamide containing supplement to treat and prevent this deficiency and it is a good idea to get enough niacin if you are at risk of deficiency for other reasons (approximately 40mg nicotinamide a day). Niacin or niacinamide may cause flushing!

B6-Pyridoxine

Vitamin levels are not usually tested but measurement of serum pyridoxal phosphate is most commonly used.

Vitamin B6 comprises 3 forms: pyridoxine, pyridoxal and pyridoxamine, and has a central role in the metabolism of amino acids. It is involved in the breaking down of glycogen into glucose. In addition, vitamin B6 plays a key role in metabolism of neurotransmitters, such as dopamine and serotonin, and it ensures efficient functioning of the immune system and making of red blood cells. The symptoms of vitamin B6 deficiency are local inflammation of the skin and dysfunction of the nervous system. Some NET patients may be at risk of deficiency due to malabsorption in the intestines and undernutrition.  If you are worried you may have lower levels make sure you consume enough (1.4mg per day). If you are deficient you diet must be supplemented.

B9-Folate

Serum folate reflects folate status unless intake has recently increased or decreased.

Folic acid is the synthetic form of folate. It is used in supplements and for food fortification. Folate functions together with vitamin B12 to form healthy red blood cells. It is also required for normal cell division and the normal structure of the nervous system.  It is possible to become deficient in folate due to malabsorption of nutrients in the intestine through diarrhoea and other malabsorption states such as surgery. If you are worried you may be at risk of deficiency ensure you get enough folate/folic acid (200 µg per day). If you are deficient your diet will need to be supplemented.

B12-Cobalamin

Vitamin B 12 must be measured alongside complete blood count and folate levels.

Cobalamin plays a role in DNA synthesis and regenerates methionine for protein synthesis. Low vitamin B12 levels have been observed in NET patients receiving somatostatin analogues and therefore monitoring of vitamin B12 levels is important during long-term therapy. Vitamin B12 deficiency has also been found to be common in type 1 gastric carcinoid NETs after Antrectomy and/or Gastrectomy. Patients with diseased or surgically removed ileums (end of the small bowel) and those who have bacterial overgrowth in the area are also at risk of Vitamin B12 deficiency. In addition, patients with insufficient pancreatic enzymes are also at risk of vitamin B12 deficiency as they play a key role in the steps before absorption occurs. If you are worried your levels may be low you must consume 2.5µg a day. If you are clinically deficient your diet must be supplemented, usually with regular injections.

Fat Soluble Vitamins

A, D, E and K

Somatostatin Analogues (Octreotide and Lanreotide) based injection treatments for a variety of NETs may cause deficiencies in some vitamins. This is because they may alter absorption of dietary fats which contain vitamins. Enzymes are usually released from the pancreas to break down nutrients such as fat, but pancreatic enzyme release can be reduced when somatostatin analogue medications are given.  When fat is not broken down properly, stools become pale/yellow, loose, greasy, foul-smelling or frothy and floating –‘steatorrhoea’. Your precious vitamins therefore end up in your toilet instead. One study followed 54 patients, who mostly had carcinoid tumours and were on somatostatin analogues for at least 18 months. It found that only one fifth of patients had visible steatorrhoea, but 6% were deficient in vitamin A, 28% deficient in D, 58% in E and 63% in K1. This shows that even if you don’t have visible signs of steatorrhoea, you may still be deficient in one or more vitamin!

A-Retinol

Serum retinol blood tests are the means of measuring vitamin A in the body.

Vitamin A is a fat soluble vitamin absorbed through the small intestine either as retinol or carotene, and then converted to retinyl palmitate which is stored in the liver. Normally the liver contains a 2 year store of vitamin A. Vitamin A deficiency has a wide range of ocular manifestations including conjunctival and corneal xerosis, keratomalacia, retinopathy, visual loss, and nyctalopia, or night blindness, which is the earliest and most common symptom. If you are worried about having low levels make sure you consume enough (800 µg per day). If you are deficient your diet will need to be supplemented.

D 3 –cholecalciferol

Your 25(OH)D levels can be measured with a simple blood test.

Cholecalciferol is a nutrient and hormone. Recent evidence for the non-skeletal effects (those apart from bone mineralisation) of vitamin D, coupled with recognition that vitamin D deficiency is common, has revived interest in this vitamin. Low vitamin D levels are linked to higher rates of several other cancers. Vitamin D is produced by skin exposed to ultraviolet B radiation and obtained from dietary sources, including supplements. Persons commonly at risk for vitamin D deficiency include those with inadequate sun exposure, limited oral intake, or impaired intestinal absorption from the diet (as above). The most recent evidence actually points out that the sun is not to be relied on as a source of vitamin D and oral intake is important. If you are worried you may have low levels you must speak with your doctor to arrange supplementation with or without a test.

E- α-tocopherol

Vitamin E can be tested by looking at the α-tocopherol level or ratio of serum α-tocopherol to serum lipids.

Vitamin E is a powerful antioxidant that can be regenerated by vitamin C after oxidation in the human body. It prevents damage of polyunsaturated fatty acids in cellular membranes. Signs of deficiency include dry skin and neurological symptoms. If you think you may have low levels make sure you consume enough (12mg per day). If you are deficient your diet will have to be supplemented.

K- Phylloquinone

Vitamin K deficiency can be measured by looking at the prothrombin time.

Phylloquinone is required for blood clotting and deficiency results in bleeding. Since this deficiency is common in patients with fat malabsorption due to severe liver disease and somatostatin analogue treatment it is important that you consume enough (75 µg per day). If you are clinically deficient you will need to receive supplementation.

Summary

Of course these are only the nutrients which are at risk of deficiency, there are many other nutrients and botanical extracts which may help patients with NET’s. It is vital that nutrition is considered for every patient with a NET and we hope one day each NET unit will have NET Specialist Dietitian to make this possible.

It is vital that nutrition is considered


Links to the other nutrition blogs:

Article 2 – Gastrointestinal Malabsorption.  Overlapping slightly into Article 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 discussed 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.

Article 5 – ‘Pancreatic Enzyme Replacement Therapy’. The role of PERT (Creon etc) in helping NET Patients.

You may also appreciate these articles where there is overlap:

The Diarrhea Jigsaw – different things can cause diarrhea, it’s not all about syndromes.

The Constipated NET Patient – yes they exist!

Very grateful to Tara for the input.

Other useful links which have an association to this blog:

{a} Read a Nutrition Booklet co-authored by Tara – CLICK HERE

{b} Follow Tara on Twitter – CLICK HERE

{c} Watch a video of Tara presenting to a group of NET Patients – CLICK HERE

{d} Now Watch Tara answering the Q&A from patients – I enjoyed this – NET patients are very inquisitive! CLICK HERE

Thanks for listening

Ronny

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Neuroendocrine Cancer – Hormones

HormonesNET 2018

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

Hormones – the NET Effect

At least one or more hormones will be involved at various sites and even within certain syndromes, the dominant and offending hormone may differ between anatomical tumour sites. For example, NETs of the small intestine, lung or appendix (and one or two other places) may overproduce serotonin and other hormones which can cause a characteristic collection of symptoms currently called carcinoid syndrome.   The key symptoms are flushing, diarrhea and general abdominal pain, loss of appetite, fast heart rate and shortness of breath and wheezing. The main symptom for me was facial flushing and this was instrumental in my eventual diagnosis. The fact that I was syndromic at the point of diagnosis made it easier to discover, albeit the trigger for the investigation was a fairly innocuous event.  Other types of NETs are also affected by the overproduction of hormones including Insulinomas, Gastrinomas, Glucagonomas, VIPomas, Somatostatinomas, and others.  These can cause their own syndromes and are not part of carcinoid syndrome as some organisations incorrectly state. For more on NET syndromes – Read Here.

So are hormones horrible? 

Absolutely not, they are essential to the normal function of the human body.  For example if you didn’t have any of the hormone Serotonin in your system, you would become extremely ill.  On the other hand, if your glands start secreting too much of certain hormones, your body could become dysfunctional and in some scenarios, this situation could become life threatening.  So hormones are good as long as the balance is correct. NET patients with an oversecreting tumor may be classed as “functional”.

  • Functional tumors make extra amounts of hormones, such as gastrin, insulin, and glucagon, that cause signs and symptoms.
  • Nonfunctional tumors do not make extra amounts of hormones. Signs and symptoms are caused by the tumor as it spreads and grows. Many NET patients are deemed to be “non-functioning” with normal hormone levels. It’s also accurate to say that many can move from one stage to the other.

Location Location Location

It’s accurate to say that the type and amount of hormone secretion differs between locations or sites of the functional tumor and this can also create different effects.  The division of NETs into larger anatomical regions appears to differ depending on where you look but they all look something likes this:

Foregut NETs: In the respiratory tract, thymus, stomach, duodenum, and pancreas. This group mostly lack the enzyme aromatic amino decarboxylase that converts 5-HTP (5-Hydroxytryptophan – a precursor to serotonin) to serotonin (5-HT); such tumours tend to produce 5-HTP and histamine instead of serotonin.  The Pancreas is a particularly prominent endocrine organ and can produce a number of different syndromes each with their associated hormone oversecretion – although many can be non-functional (at least to begin with). Please note the respiratory tract and thymus are not really ‘Foregut’ but grouped there for convenience. 

Midgut NETs: In the small intestine, appendix, and ascending colon. For example, serotonin secreting tumors tend to be associated with carcinoid syndrome which tends to be associated with midgut NETs and this is normally the case. Many texts will also tell you that a syndrome only occurs at a metastatic stage.  Both are a good rule of thumb but both are technically incorrect. For example, in the bronchus or ovary you can have a form of carcinoid syndrome without liver metastasis (tends to be described as atypical carcinoid syndrome). It’s also possible to see serotonin secreting tumors in places such as the pancreas (although what you would call that type of NET is open for debate).

Hindgut NETs (transverse, descending colon and rectum) cannot convert tryptophan to serotonin and other metabolites and therefore rarely cause carcinoid syndrome even if they metastasise to the liver.

Less Common Locations – there are quite a few less common NET locations which may involve less common hormones – some are covered below including the key glands contributing to NETs.

Unknown Primary? –  One clue to finding the primary might be by isolating an offending hormone causing symptoms.

The key NET hormones

Serotonin

I used the example of Serotonin above 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.

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 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 nonfunctional:

  • 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.

The pancreas is one of the ‘3 p’ locations often connected to Multiple Endocrine Neoplasia – MEN 1

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 pancretic 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 simultanously 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 a read 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.

Thanks for reading

Ronny

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