| Bowel cancer | Diagnosing bowel cancer | Treatment for bowel cancer |
| Having a stoma | Bowel cancer screening |
Reviewed by:
Dr Michael Jefford MBBS, MPH, MHlthsevMt, PhD, MRACMA, FRACP
Consultant Medical Oncologist, Peter MacCallum Cancer Centre
On this page: The bowel | Bowel cancer | Causes of bowel cancer | How common is bowel cancer?
Taken from 
Bowel cancer booklet (2MB)
The bowelThe bowel is the longest part of the digestive system (the ‘gut'). The digestive system is the long tube that runs from the back of the mouth, forms the stomach and bowel, then ends at the anus. It winds around inside the body. Food passes through it and is digested and absorbed. The waste products are passed out as bowel motions.
The bowel is made up of two sections. The small bowel is where food is absorbed. This leads into the large bowel, where only water and salts are absorbed. The large bowel has two parts: the colon, which is about one and a half metres long, and the rectum, which is about 15 centimetres long. The rectum leads to the outside of the body through the anus.
Bowel cancer generally affects the colon or rectum. Cancer of the small bowel is rare. Bowel cancer starts in the lining of the bowel (the mucosa). If untreated it spreads deeper into the wall of the bowel. From there, it can spread to lymph nodes in the area. Later, bowel cancer can spread to the liver or lungs.
Sometimes bowel cancer starts in polyps, which grow in the lining of the bowel. Polyps look like small mushrooms. These polyps are quite common in people over the age of 50 and are usually benign. However, some polyps can grow and become cancerous. People with familial adenomatous polyposis (FAP) have a lot of polyps in their bowel. They are at much greater risk of bowel cancer.
The causes of bowel cancer are not clearly understood. Some risk factors make it more likely that a person will develop bowel cancer. These include:
Bowel cancer is the most common cancer that affects men and women in Victoria. More than 3400 people are diagnosed each year. Bowel cancer mainly affects people over the age of 50 but can occur at any age.
