Bowel cancer is cancer in any part of the colon or rectum. Bowel cancer can develop in two ways: it can grow from the inner lining of the bowel, or from small growths on the bowel wall called polyps. These mushroom-shaped growths are usually harmless (benign) but may become cancerous over time.
If untreated, bowel cancer can spread (metastasise) deeper into the wall of the bowel. From there it can spread to the lymph nodes (glands).
Lymph nodes are small, bean-shaped masses that collect and destroy bacteria and viruses in the body. They are part of the body’s lymphatic system, which plays an important role in the functioning of the immune system.
Later, bowel cancer can spread to other organs such as the liver or lungs. In most cases, it develops fairly slowly and may stay in the bowel for months or years before spreading.
The colon and rectum together are known as the large bowel. The word colorectal is commonly used to describe cancers of the colon or rectum. Bowel cancer is also called colorectal cancer. The terms large intestine, large bowel and colon all refer to the same organ.
Last Reviewed: 01 February 2011