Colorectal cancer, also known as colon cancer, rectal cancer, or bowel cancer, is a cancer from uncontrolled cell growth in the colon or rectum (parts of the large intestine), or in the appendix. It is most common in people over the age of 45 with one in 18 people in the UK developing bowel cancer at some point in their lives. It is more easily and successfully treated if diagnosed in its early stages.

The Causes

The exact causes are not known although certain factors make the cancer more likely:

  • A family history of colorectal cancer
  • Lack of exercise
  • Lack of fibre, fruit and vegetables in your diet as well as processed red meats
  • Previous cases of colorectal cancer, chronic bowel inflammation (e.g. ulcerative colitis) or adenomatous polyp.

The bowel forms part of our intestines and is divided into two parts, the small bowel and the large bowel. The large bowel is made up of the colon and rectum with cancer occurring in either of these areas.

The Symptoms

  • Blood or mucus in the stools (although blood is often from piles)
  • Anaemia
  • Diarrhoea or constipation lasting longer than normal
  • Abdominal pain
  • Loss of weight
  • Fatigue

Often these symptoms are similar to a number of other minor conditions but if you do have any of these symptoms you should contact your doctor as soon as possible.


A diagnosis is made by a variety of tests including the appearance of the stools, a rectal examination, a faecal occult blood test, a barium X-ray, colonoscopy and a biopsy. The faecal occult blood test (which looks for traces of blood in the stools) is not by itself sufficient to produce a diagnosis of bowel cancer but is a popular and effective first step in the diagnostic process.


If bowel cancer is diagnosed, in about 60% of cases surgery will be required to remove the malignant section of the bowel. The earlier the disease is detected the better the chances of successful treatment. Regular screens improve the chances of detecting the disease at any early stage.