Neuroendocrine tumours are cancers.
They usually originate in the neuroendocrine cells.
These cells are a very particular type of neuron (nerve cell) that can also release hormones.
This makes them somewhere between a nerve cell and an endocrine cell.
This means that they can both transmit electrochemical signals and secrete hormones, which can go via the bloodstream to far away target cells.
Neuroendocrine cells are found in many sites in the body, including the hypothalamus (in your brain), pancreas, adrenals, airways and gastrointestinal tract.
They are also found in the epithelium (lining) of your cardiovascular system and genitourinary tract.
All of them form part of the endocrine system, which is super-important in regulating your metabolism, reproduction and homeostasis.
No, they are rare.
There are many types of neuroendocrine tumours (also called NETS).
They may grow slowly or they can grow fast.
Some of them release excess hormones; these are called functional neuroendocrine tumours.
Others do not release hormones or not enough to cause you symptoms.
Hence, they are called non-functional neuroendocrine tumours.
The commonest NET is in the gastrointestinal tract, occurring most frequently in the small intestines, appendix and rectum.
Around 65% of all neuroendocrine tumours are gastrointestinal tract ones.
Many of them grow slowly, but the occasional one can be aggressive.
If you have this tumour, it can cause non-specific abdominal symptoms, such as abdominal pain, diarrhoea, cramps and weight loss.
Some of them can spread to the liver, causing something called carcinoid syndrome.
Once in the liver, the metastatic tumour sites can release hormones into the bloodstream.
Then you may have symptoms like flushing.
Yes, though these are very rare.
These are called islet cell tumours as they originate in the islets of Langerhan in the pancreas, which are the hormone-producing cells in that organ.
Most pancreatic neuroendocrine tumours do not produce hormones.
But when they do, the tumours are named after the hormone they produce, e.g. insulinomas produce an excess of insulin, and glucagonomas produce an excess of glucagon.
Therefore, the symptoms are those of an excess of that particular hormone.
If you have too much insulin, you may have hypoglycaemia (i.e. low blood sugar), especially in the mornings.
Then you may experience dizziness, palpitations, sweating, intense hunger and sweating.
Some people even go into a coma.
Glucagonomas produce too much glucagon, which leads to hyperglycaemia (i.e. high blood sugar).
Therefore, you may have symptoms typical of diabetes, such as thirst and excessive urination.
You may also have unexplained weight loss because glucagon breaks down a lot of fat and protein.
A hallmark rash is stereotypical of a glucagonoma.
These are painful, itchy blisters that crust over and leave brown patches.
This is a cancer that originates in the adrenal glands, which are small glands on top of your two kidneys.
The adrenal gland is the one that makes cortisol, adrenaline, noradrenaline, aldosterone and certain sex hormones.
It is responsible for your “fight or flight” response, blood pressure, fluid balance and metabolism.
It is rarer than the gastrointestinal NETs, but if it does occur, it is most likely to affect children younger than five years old and adults in their 40s and 50s.
Fortunately, most growths in the adrenal gland are not cancer, but adenomas, which are benign tumours.
They too can be either functioning (i.e. secrete excess adrenal hormones) or non-functioning.
Like with most cancers, it depends on the stage when it is diagnosed.
Most early neuroendocrine cancers can be cured.
Many of them grow very slowly or present with symptoms of excess hormones that allow you to detect them earlier rather than later.
Many a time, a surgeon is required to remove the neuroendocrine cancer.
Then chemotherapy may be given to kill the cancer cells around the excised wound or the ones that cannot be seen.
If the tumour is not removable, chemotherapy may be the first option.
There is also targeted therapy, radiotherapy and immunotherapy.
Dr YLM graduated as a medical doctor, and has been writing for many years on various subjects such as medicine, health, computers and entertainment. For further information, email starhealth@thestar.com.my. The information provided is for educational and communication purposes only, and it should not be construed as personal medical advice. Neither The Star nor the author gives any warranty on accuracy, completeness, functionality, usefulness or other assurances as to such information. The Star and the author disclaim all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.
