Colorectal cancer
The bowel is part of the digestive system stretching from the stomach to the anus. It is a hollow tube coiled up in your abdomen, divided into two parts: the small bowel and the large bowel (the colon and the rectum). Cancer in the large bowel is known as colorectal cancer.
Causes of colorectal cancer
Each year there are over 34,000 new cases of colorectal cancer in the UK. Similar numbers of men and women are affected, usually over the age of 45 years.
Unfortunately we still know very little about the causes of cancer of the large bowel, also called colorectal cancer. However, studies have shown that the frequency of bowel cancer is greater in countries which eat a diet high in fat and low in fibre (roughage). It has been suggested that a high alcohol intake, particularly of beer, may be linked to this cancer.
There are two inherited conditions that can increase the risk of developing colorectal cancer. They are Familial Adenomatous Polyposis (FAP) and Hereditary Non-Polyposis Colon Cancer (HNPCC). Together, they account for 5% of bowel cancers.
A history of severe ulcerative colitis or Crohn’s disease affecting the large bowel may also increase the risk of developing colorectal cancer.
Symptoms
The commonest symptom of colorectal cancer is a change of bowel habits. There may be increasing constipation, or perhaps alternating bouts of constipation and diarrhoea. There may be blood or mucus in the stools. A feeling that you haven't completely emptied your bowels is quite common if the tumour is in the rectum. This can be uncomfortable and you may constantly feel the urge to go to the toilet.
You may feel a colicky type pain, or vague discomfort in your abdomen. You may also feel generally unwell, for example listless or tired, because you have been losing blood from the bowel and may have become anaemic (lack of red blood cells).
If your symptoms have lasted six or more weeks, including bleeding from the rectum, you need to see a specialist.