What is small bowel cancer?

The small bowel makes up most of the digestive system and helps your body to digest food and take in vitamins. Cancer that starts here is called small bowel cancer.

The small bowel is between 4 and 6 metres long and is made up of 3 parts. The:

  • duodenum (dew-oh-dean-um) – the top part of the small bowel, which connects to the stomach
  • jejunum (jej-you-num) – the middle part
  • ileum (ill-ee-um) – the lower part, which connects to the large bowel (colon)

Most cases of small bowel cancer are found in the duodenum.

Diagram showing the position of the small bowel
Diagram showing the parts of the small bowel

How common are small bowel cancers?

Cancers of the small bowel are rare. Around 1,900 people are diagnosed in the UK each year.

Whereas, around 44,100 cases of cancer of the large bowel (colon) and rectum are diagnosed each year.

Risks and causes

We don’t know what causes most small bowel cancers. But there are some factors that may increase your risk.

  • age - small bowel cancer is more common in older people.
  • familial adenomatous polyposis – a rare condition where an inherited faulty gene makes many polyps develop on the bowel lining
  • Lynch syndrome (Hereditary non polyposis colorectal cancer or HNPCC) - a gene fault that increases the risk of several different types of cancer at a younger age
  • Peutz Jeghers syndrome – an inherited condition where benign (non cancerous) polyps form in the bowel.
  • Crohn’s disease – cancers related to Crohn’s disease are usually adenocarcinomas of the ileum. Only 2 out of 100 people with Crohn's disease (2%) will develop cancer in the small bowel
  • Coeliac disease – may slightly increase your risk of developing lymphoma or adenocarcinoma of the small bowel. Sticking to a gluten free diet reduces the risk
  • a diet rich in red meat or smoked foods, or a high fat diet

Smoking and drinking alcohol has also been linked to the risk of small bowel cancer, but we need further research to confirm this.

Types of small bowel cancer

Tumours of the small bowel may be either non cancerous (benign) or cancerous (malignant). Benign tumours include polyps and lipomas

There are different types of malignant small bowel tumour.

Getting diagnosed

You usually start by seeing your GP. They will ask you about your general health and symptoms and will also examine you.

Last reviewed: 
29 Mar 2022
Next review due: 
29 Mar 2025

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