About bowel cancer

What does the bowel do?

The bowel is part of our digestive system and is divided into the small and large bowel. The large bowel is made up of the colon and rectum. Food passes from the stomach to the small bowel. After the small bowel takes nutrients into the body any undigested food passes through the large bowel where water is removed from the waste matter. This waste matter is held in the rectum (back passage) until it leaves the body as bowel motions (also known as stools or faeces).

What is bowel cancer?

Bowel cancer is also known as colon, rectal or colorectal cancer. The lining of the bowel is made of cells that are constantly being renewed. Sometimes these cells grow too quickly forming a clump of cells known as a bowel polyp (sometimes known as an adenoma). Polyps are not bowel cancers (they are usually benign) but they can change into a malignant cancer over a number of years. A malignant cancer is when cancer cells have the ability to spread beyond the original site and into other parts of the body.

How common is bowel cancer?

Bowel cancer is the second most common type of cancer found in men and women in Northern Ireland. About 1 in 20 people will develop bowel cancer in their lifetime. Bowel cancer is more common in older people, with around 80% bowel cancers occurring in people over 60 or over.

What are the symptoms of bowel cancer?

Bowel cancer can develop at any time between screening tests. Do not ignore the following symptoms:

• Unexpected, painless bleeding from your back passage, or blood in your stools. If you see blood in your stools, you should see your GP immediately. Finding a little bright red blood just on the toilet paper probably does not matter. If it continues for two or three weeks, see your GP.

• A change in your bowel habit. You may develop loose bowel motions, or you may pass a slimy substance called mucus. Sometimes you may become constipated. Look out for constipation and diarrhoea combined. If you experience these symptoms for more than six weeks, you should see your GP. If you have these symptoms as well as others in this list, see your GP as soon as possible.

• Pain or swelling in your abdomen (belly or tummy).

• Unexplained weight loss.

• Unexplained anaemia (thinning of the blood). This can make you feel extremely tired. It is usually discovered by a blood test done by your GP.

All these symptoms can be caused by other conditions. For example, haemorrhoids (piles) often bleed.