Neuroendocrine Tumour Symptoms – Everything You Should Know

Key Takeaways A neuroendocrine tumour (NET) starts in hormone-producing cells found in many organs, most often the gut, pancreas and lungs. Many NETs grow slowly and cause no symptoms for years. When symptoms appear they depend on where the tumour is and whether it releases hormones. Carcinoid syndrome, with flushing, diarrhoea and wheezing, happens in some people whose tumour releases serotonin and other substances, usually after it has spread to the liver. A pancreatic neuroendocrine tumour can cause symptoms from too much insulin, gastrin or other hormones, or from pressure on nearby organs. Diagnosis uses blood and urine tests, scans, endoscopy and a biopsy. Treatment depends on the grade, size, location and spread. Surgery, medicines, targeted radiation and chemotherapy may all be used.

A neuroendocrine tumour is an unusual cancer, and it is easy to miss. The symptoms can look like irritable bowel, asthma, acidity or menopause, so many people are treated for something else for months or years before the right test is done.

This guide explains what a neuroendocrine tumour is, the symptoms to watch for in different parts of the body, what carcinoid syndrome means and how doctors confirm the diagnosis. It is meant to help you understand what to ask your doctor. It cannot replace an examination.

What Is a Neuroendocrine Tumour?

If you are searching what is neuroendocrine tumor, the simple answer is this. Your body has neuroendocrine cells that act like a link between the nervous system and the hormone system. They make hormones that control digestion, blood sugar, breathing and other functions. A neuroendocrine tumour, also written neuroendocrine tumor and often shortened to NET, is a growth that starts in these cells.

NETs can arise almost anywhere, but they are most often found in the small intestine, appendix, rectum, pancreas and lungs (Oronsky et al., 2017). Studies from the United States show that the number of people diagnosed with NETs has risen over the past few decades, partly because scans and endoscopy now find small tumours that were once missed (Dasari et al., 2017).

Neuroendocrine tumour vs neuroendocrine cancer

The words neuroendocrine tumour and neuroendocrine cancer are used for the same family of growths, and you will hear both. Doctors divide them by grade, which tells how fast the cells are dividing. Grade 1 and grade 2 tumours are called well-differentiated and tend to grow slowly. Poorly differentiated neuroendocrine carcinomas are fast-growing and behave differently. Your report will state the grade, and it strongly shapes the treatment plan (Pavel et al., 2020).

Neuroendocrine Tumour Symptoms

When neuroendocrine tumor symptoms do appear, they come from two sources. The tumour can press on or block the organ it sits in. Or it can release hormones into the blood and cause symptoms in other parts of the body.

Where the tumour is	Symptoms that may appear
Small intestine or appendix	Belly pain, bloating, blockage, weight loss, sometimes found during surgery for another reason
Rectum or stomach	Bleeding, a change in bowel habit, pain or no symptoms at all
Lung	Cough, wheeze, blood in sputum, repeated chest infections, breathlessness
Pancreas	Belly or back pain, jaundice, weight loss, or hormone-related symptoms
Liver (spread from elsewhere)	Swelling or pain in the upper right belly, tiredness, carcinoid syndrome

General symptoms such as tiredness, weight loss and loss of appetite can occur with any NET. These are not specific, which is why NETs are often found late. If you have any of these problems and they last for more than a few weeks, get them checked.

Carcinoid Syndrome

Carcinoid syndrome is a group of symptoms caused when a tumour releases serotonin and other chemicals into the blood. It usually happens when a NET of the gut has spread to the liver, because the liver would otherwise clear these chemicals before they reach the rest of the body (Oronsky et al., 2017).

The common signs are:

• Flushing of the face and upper chest, with warmth and redness that comes and goes
• Watery diarrhoea and cramping
• Wheezing or breathlessness
• A fast heartbeat
• Over time, thickening of the heart valves on the right side, which is known as carcinoid heart disease

Flushing and diarrhoea are also common with food, alcohol, menopause and gut infections, so these symptoms alone do not mean you have carcinoid syndrome. A doctor can test for the specific marker, which is a breakdown product of serotonin measured in urine or blood.

Pancreatic Neuroendocrine Tumour Symptoms

A pancreatic neuroendocrine tumor starts in the hormone-producing islet cells of the pancreas. It is rarer than the more common pancreatic cancer, and it behaves differently. It often grows more slowly (Pavel et al., 2020). Some of these tumours release hormones and cause symptoms such as:

• Repeated low blood sugar with sweating, shakiness and confusion, from too much insulin
• Stomach ulcers, burning pain and diarrhoea, from too much gastrin
• A rash, weight loss and a high blood sugar level from other hormones

Tumours that do not release hormones cause symptoms only when they grow large enough to press on the bile duct or nearby organs. Then the signs may be jaundice, belly pain or weight loss.

How Is a Neuroendocrine Tumour Diagnosed?

Because the symptoms are vague, diagnosis usually needs several steps. Your doctor will ask about your symptoms and examine you, then may advise some or all of these tests (Pavel et al., 2020).

• Blood and urine tests. These can measure chromogranin A and serotonin breakdown products. They support the diagnosis but cannot confirm it alone.
• Imaging. CT or MRI scans show the size and spread of the tumour. A special PET scan that uses a tracer targeting somatostatin receptors can find small NETs.
• Endoscopy or colonoscopy. A camera test looks for tumours in the stomach, bowel or rectum.
• Biopsy. A small sample of tissue is studied under a microscope. It confirms the tumour type and gives the grade.

Neuroendocrine Tumour Treatment

Neuroendocrine tumor treatment depends on the grade, size, location and whether the tumour has spread. It is planned by a team that may include a surgeon, an oncologist, a gastroenterologist and a radiologist.

Treatment	Description
Surgery	Removing the tumour is the main treatment when it is limited to one area. Small tumours in the appendix or rectum may need only a minor procedure.
Medicines that control hormones	Somatostatin analogues can ease flushing and diarrhoea in carcinoid syndrome and may slow tumour growth.
Targeted and radioligand treatment	Some NETs are treated with targeted tablets or with a radioactive medicine that homes in on the tumour cells.
Chemotherapy	It is more often used for fast-growing or pancreatic tumours.
Liver-directed treatment	When the tumour has spread to the liver, procedures that block its blood supply or burn the deposits may be considered.
Active watching	Some small, slow-growing tumours are watched with regular scans instead of treated straight away.

If symptoms are a concern, supportive care can sit alongside treatment.

Expert Insight “Neuroendocrine tumours are easy to mistake for common conditions. If flushing, diarrhoea or belly pain keeps coming back and no one has found the cause, it is reasonable to ask whether a NET could be considered. The grade of the tumour matters as much as its size.” Dr. Tarang Krishna MD Managing Director, Cancer Healer Center

When Should You See a Doctor?

See a doctor if you have flushing or diarrhoea that keeps returning without a clear cause, unexplained weight loss, belly pain that does not settle, jaundice, repeated low blood sugar, or a cough and wheeze that do not respond to the usual treatment. A family history of NETs or a related genetic condition is also worth mentioning.

Go to an emergency department for severe belly pain with vomiting, black or bloody stools, yellow skin with fever, or fainting and confusion.

Support for Neuroendocrine Tumours at Cancer Healer Center

Cancer Healer Center offers consultations for people with neuroendocrine tumours and their families, including remote consultations for those who prefer care from home. The centre also offers Cancer Healer Therapy (CAM), a herbal-based supportive approach meant to be used alongside the treatment prescribed by your oncologist and not instead of it. Patients are encouraged to keep their oncologist informed about any herbal products they use to support coordinated care. You can explore the Cancer Healer Center locations to find a centre convenient for you.

References

Dasari, A., Shen, C., Halperin, D., et al. (2017) ‘Trends in the incidence, prevalence, and survival outcomes in patients with neuroendocrine tumors in the United States’, JAMA Oncology, 3(10), pp. 1335-1342. doi:10.1001/jamaoncol.2017.0589.

Oronsky, B., Ma, P.C., Morgensztern, D. and Carter, C.A. (2017) ‘Nothing but NET: a review of neuroendocrine tumors and carcinomas’, Neoplasia, 19(12), pp. 991-1002. doi:10.1016/j.neo.2017.09.002.

Pavel, M., Oberg, K., Falconi, M., et al. (2020) ‘Gastroenteropancreatic neuroendocrine neoplasms: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up’, Annals of Oncology, 31(7), pp. 844-860. doi:10.1016/j.annonc.2020.03.304.