Small bowel cancer
Small bowel cancer – or small intestine cancer - is cancer affecting the small intestine (small bowel) which lies between the stomach and the colon (large bowel).
Small bowel cancer is rare with almost 1,500 people diagnosed with it in the UK every year.
The main types of small bowel cancer are named after the cells where they develop: adenocarcinoma, sarcoma, neuroendocrine tumours (including carcinoid tumours) and lymphoma.
The small bowel is around 6 metres (over 19 feet) long. Its main job is to digest and absorb vitamins, minerals and nutrients.
The 3 parts of the small bowel are the duodenum at the top, jejunum in the middle, and the lower part is the ileum.
Types of small bowel cancer
Adenocarcinoma: Adenocarcinoma is the most common type of small bowel cancer which begins in the epithelial cells lining the bowel, usually developing in the duodenum.
Neuroendocrine tumours: Neuroendocrine tumours - including carcinoid tumours - develop from hormone producing cells, usually in the appendix or the ileum.
Lymphoma: Lymphomas are usually found in the jejunum.
Sarcomas: Sarcomas develop in soft tissues usually in the ileum but can affect any part of the small bowel.
The small bowel may also be affected by cancers that began elsewhere in the body. When this occurs the cancer in the small bowel is called a secondary cancer.
Small bowel cancer risk factors
It is not clear why some people develop small bowel cancer, but genetics influences some cases:
- Familial adenomatous polyposis - in which an inherited faulty gene causes polyps to develop on the lining of the bowel. Gardner syndrome is a subtype of FAP.
- Hereditary non-polyposis colorectal cancer , (HNPCC or Lynch syndrome) - in which there’s a rare genetic fault.
- Peutz Jeghers syndrome - where benign polyps form in the bowel.
- Crohn’s disease related cancers tend to be adenocarcinomas in the ileum
- Coeliac diseasemay cause a slightly increased risk of developing lymphoma or adenocarcinoma of the small bowel.
- Lifestyle factors may affect small bowel cancer risk, including eating a diet rich in red meat, smoked foods, or high in fat.
- Smoking and drinking alcohol may also affect a person's small bowel cancer risk.
Small bowel cancer symptoms
The symptoms of small bowel cancer can be similar to those of other conditions, making it less likely that a person or their doctor will suspect small bowel cancer.
Small bowel cancer symptoms include:
Diagnosis of small bowel cancer
The small bowel is deep inside the body, making it hard to examine or for samples to be taken with a biopsy using endoscopy or colonoscopy. Other tests may be arranged including:
- Barium X-ray taken after drinking a special liquid and tracking its progress through the bowels.
- Blood test for low red cell count or anaemia, and liver tests.
- A CT scan or chest X-ray may be carried out to see if cancer has spread from the small bowel.
- Capsule endoscopy uses a small capsule containing a camera and light that is swallowed and takes pictures of the bowel from the inside.