Small bowel neuroendocrine cancer
Small bowel neuroendocrine cancers are rare. They start in the neuroendocrine cells of the .
The small bowel is part of the . It is also called the small intestine.
Read more general information about the difference between NETs and NECs
The small bowel makes up most of the digestive tract. It is about 6 metres long, but it is folded up so that it fits inside the abdomen.
It has 3 sections:
duodenum (dew-oh-dean-um) – this is just beyond the lower part of the stomach and is the top part of the small bowel, connecting it to the stomach
jejunum (jej-you-num) – the middle part
ileum (ill-ee-um) – the lower part, which connects to the large bowel (colon)
Right at the end of the ileum, just before it joins to the colon, is a small pouch called the appendix.
Small bowel neuroendocrine cancers are rare. Around 610 people are diagnosed with a small bowel neuroendocrine cancer every year in England.
There are different types of cancer that can start in the small bowel. Around 40 out of 100 (around 40%) of small bowel cancers are neuroendocrine cancers.
A risk factor is anything that increases your risk of getting a disease. Different diseases have different risk factors. Small bowel neuroendocrine cancers are rare. At the moment, there are no clear risk factors for small bowel neuroendocrine cancer.
Having a family history of cancer is a risk factor for all types of neuroendocrine cancer. This includes small bowel neuroendocrine cancers. Rarely, more than one person in a family develop a small bowel NET, although it is more common for this not to happen. Some people with a small bowel NET develop another small bowel NET in the future.
Read more about the risks and causes of neuroendocrine cancer
Not everyone with a small bowel neuroendocrine cancer has symptoms. Doctors often diagnose a stomach neuroendocrine cancer when looking for something else. For example, a doctor might see the cancer on a CT scan which you have for another reason.
If you do have symptoms, they might be unspecific. They can be similar to other conditions that aren’t caused by a neuroendocrine cancer. Symptoms are usually caused by:
the growth of the cancer in your small intestine or in nearby
the neuroendocrine cancer spreading to other parts of the body
hormones made by the cancer
Symptoms might include:
tummy (abdominal) pain
weight loss
changes to your poo such as diarrhoea
bleeding in your digestive system – this might cause your poo to be black or blood in your vomit
feeling or being sick
feeling very tired
Some small bowel neuroendocrine cancers make hormones that go into the bloodstream. Doctors call these functioning tumours. These hormones can cause symptoms. Doctors call this collection of symptoms carcinoid syndrome. It is more likely to happen if the cancer has spread to other parts of the body, especially the liver.
The symptoms might include:
flushing of your skin
diarrhoea
wheezing
fast heart beat
Read more about carcinoid syndrome
Your cancer might not cause any symptoms. Your doctor might diagnose a small bowel neuroendocrine cancer during tests for something else.
If you have symptoms, you usually see your GP first. They might organise some tests. Your GP will decide if you need to see a specialist. They might refer you to a specialist. These doctors specialise in problems affecting the digestive system.
Find out more about seeing a specialist
If your doctor suspects cancer, you have tests to check the type of cancer you have. Tests also show the size of the cancer and whether it has spread. This helps your doctor plan your treatment.
Tests might include:
blood tests - these check your general health and check levels of substances raised by neuroendocrine cancer
urine tests to check for a substance raised by neuroendocrine cancer
– this is to look inside your food pipe, stomach and small intestine and take a cancer sample ()
capsule endoscopy - you swallow a small disposable camera inside a capsule which transmits pictures
to look inside your large bowel and see the end part of your small intestine
of your chest and tummy
of your tummy
radioactive scans – these are octreotide scans (or ) and MIBG scans
– this test checks your heart
You swallow a small capsule, which contains a camera and light source and takes pictures of the bowel as it travels through. The capsule is the size of a large pill.
A DBE is a type of endoscopy. You usually have a capsule endoscopy first and then a DBE as a follow up.
An endoscopist (a specially trained healthcare professional) inserts a small flexible tube, through the mouth or the back passage (rectum). The tube is called a double balloon enteroscope. This allows them to examine the small bowel and take a biopsy if necessary.
You usually have a and it can take many hours. So doctors don't often use this test.
Read more about tests to diagnose neuroendocrine cancer
The best person to talk to you about your outlook () is your doctor. Not everyone wants to know. People cope differently with cancer and want different information.
Survival depends on many factors. So no one can tell you exactly how long you will live. Your doctor might be able to give you some guide, based on their knowledge and experience.
Your prognosis will depend on whether you have a neuroendocrine carcinoma (NEC) or a neuroendocrine tumour (NET). And it will depend on where it is, and how far it has spread (stage).
Read more about survival for neuroendocrine cancer
The tests and scans you have give information about:
your type of cancer
the grade of your cancer - this is how quickly or slowly the cancer cells are growing and dividing
the stage of your cancer - this is how big the cancer is, and whether it has spread
This information helps your doctor decide which treatment you need.
Read more about grades, types and stages of small bowel neuroendocrine cancer
Last reviewed: 28 Feb 2025
Next review due: 28 Feb 2028
Neuroendocrine cancers are also called neuroendocrine neoplasms (NENs). There are 2 key groups - neuroendocrine tumours (NETs) and neuroendocrine carcinomas (NECs).
The grade refers to how quickly or slowly the cancer cells are dividing and growing. The stage of a neuroendocrine cancer tells you its size and whether it has spread. There are different types.
Treatment depends on a number of factors. These include whether you have a NET or NEC, where it is in your small bowel, whether it has spread, and how fast it is growing.
Survival (prognosis) depends on several factors. This includes your type of neuroendocrine cancer, where it is in your body, and whether it has spread.
Practical and emotional support is available to help you cope with neuroendocrine cancer.
Neuroendocrine cancers develop in cells of the neuroendocrine system. They can develop in different parts of the body including the lungs, stomach, pancreas and bowel.
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