Bowel (colorectal) cancer

Bowel cancer is when the normal cells in your bowel grow in an abnormal way to form a lump called a tumour. The bowel is part of your digestive system. This cancer may cause a blockage in your bowel, which can affect how your bowel works.

The bowel has two parts – the small bowel and the large bowel. Most cancers occur in the large bowel in the colon and rectum. Cancer of the rectum occurs very low down in your bowel close to your anus. Bowel cancer is also known as colorectal cancer or cancer of the colon or rectum. 

You can watch our bowel cancer video to find out more

The bowel is part of your digestive system. It is made up of the small bowel and the large bowel. 

The large bowel contains your colon and rectum. Most cancers occur in the large bowel.

When you swallow food, it goes from the gullet (oesophagus) to your stomach and into your small bowel. Food is digested in the small bowel and nutrients are taken into the body. In the large bowel, water is absorbed from digested food.

The waste matter that is left (called faeces, stool or poo) is stored in the rectum (back passage) until ready to pass out of the body through the anus - the opening to the outside of your body. 

Having a risk factor doesn’t mean you will get cancer. Sometimes people with no risk factors get the disease.

Read more about risk factors and reducing your risk of bowel cancer.

Medical content updated from our 'Understanding bowel (colorectal) and anal cancer' booklet (2022), reviewed by Mr Saqib Zeeshan, Consultant General and Colorectal Surgeon, Mary Sweeney, Colorectal Nurse Specialist and Teraze Toby, Daffodil Centre Nurse.