Bowel Cancer - Information on Bowel Cancer

Bowel cancer may also be called rectal, colorectal or colon cancer. However, once the cancer has spread beyond the wall of the bowel, it becomes harder to treat. The bowel cancer statistics on these pages are designed for use by health professionals. If you are looking for information because you or someone you know has been affected by bowel cancer, then the Cancer Help UK pages on bowel cancer may be more useful and relevant. Cancer Help UK also includes a straightforward guide to understanding statistics.

The large bowel, also called the colon, is the last section of your digestive system. Food passes through your small bowel (the longer, thinner part of your bowel) where nutrients are absorbed. Food waste then travels through your colon (large bowel) where it becomes more solid faces. Your colon has three sections - the ascending, transverse and descending colon. The rectum, at the end of your colon, is where faces collect before passing through your anus as a bowel movement.

The cancer develops when one of the cells in the colon develops a series of changes (mutations) in some of the genes that control how the cell divides and survives. As a result, the cell divides uncontrollably to form a clump of malignant (cancerous) cells. Initially, these cell changes commonly produce a polyp (a clump of abnormal cells the size of a pea on the end of a stalk of normal cells) called an adenoma.

The bowel is the long ‘tube’ that absorbs water and nutrients from food and processes waste products into faces. It includes the small bowel, colon and rectum. Bowel cancer is diagnosed in more than 3,400 Victorians and over 12,500 Australians every year. It mostly affects people over 50 years of age but it can happen in younger people. Cancer of the bowel is also known as colorectal cancer.

Bowel cancer is caused by the abnormal and uncontrolled growth of cells in the lining of the bowel. Usually, large bowel cancers develop from small, non-cancerous (benign) growths of tissue called polyps that can extend from the lining of the bowel wall. Sometimes these can become cancerous (malignant). If the cancer is left untreated, it can grow through the wall of your bowel and spread to other parts of your body.

Once food has been swallowed, it passes down the gullet (oesophagus) to the stomach, where digestion begins. It then passes through the small bowel, where essential nutrients are taken into the body. The digested food then moves into the large bowel, and water is absorbed by the colon. The colon starts at the bottom, right-hand side of the abdomen. The first part goes up and is known as the ascending colon. It then goes across to the left side of the abdomen. This part is called the transverse colon. It then goes down to the bottom of the abdomen: this part is called the descending colon, and ends in the sigmoid colon, rectum and anus.

Although the exact cause of bowel cancer isn't understood, it's known genetics can play a part. Specific genetic mutations can cause bowel cancer or inherited diseases known to predispose to the condition. For example, familial adenomatous polyposis (FAP) accounts for about one per cent of all cancers of the colon and rectum. It causes widespread development of polyps throughout the bowel from the teenage years onwards, many of which rapidly become cancerous.