What is bowel cancer?
Bowel cancer is cancer of the large bowel or colon which affects 34 000 people a year in the UK. The most common type is adenocarcinoma. The average 5-year survival is approximately 50%. For the individual patient survival depends on the stage of the cancer.
Tumours grow from the wall of the large bowel into the lumen. The symptoms depend on the size of the tumour and where it is along the length of the bowel. The distance from the anus is the most important factor – tumours close to the anus are likely to cause noticeable symptoms earlier than tumours far away from the anus in the caecum. There is a national screening programme for bowel cancer.
Bowel cancers in the rectum are usually called rectal cancers. Cancers anywhere else in the large bowel are called either bowel cancer, colon cancer or colorectal cancer. Alternatively they may be named according to their location along the course of the large bowel:
- Caecum – caecal cancer
- Transverse colon – colon cancer
- Descending colon – colon cancer
- Sigmoid colon – sigmoid cancer
- Rectum – rectal cancer
- Anus – anal cancer – this is rare type of cancer and is very different to colorectal cancers – it is not covered here.
The diagram shows the position of the colon in the abdomen and detail of the colon. Arrows show direction of movement of bowel contents from the caecum to the rectum.
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Amended February 2009
