Colorectal cancer

Further Information

• Canadian Digestive Health Foundation
• Colorectal Cancer Association of Canada
• Colorectal Forum
• The Canadian Society of Intestinal Research

Interactive Learning

Cancers affecting either the colon or the rectum are called colorectal cancer. Together, the colon and the rectum are known as the large bowel and are part of the body’s digestive system.

The colon is responsible for absorbing water and nutrients from undigested food products passing by. The rectum is situated at the end of the colon and stores the waste material before it is passed out of the body.

Risk Factors

The exact causes of colorectal cancer are unclear, although a number of risk factors may increase a person's chance of developing the condition. Risk increases with advancing age, a family history of colorectal cancer, and in females with a history of breast, ovary or uterus cancer.

Colorectal cancers seem to be associated with diets high in fat and calories but low in fibre, and with ulcerative colitis, a condition where the lining of the colon becomes inflamed.

Another common risk factor for colorectal cancer is the presence of polyps. These are benign growths on the inner wall of the colon or rectum. If they are left untreated, they may, over time, become cancerous. People who have any of the risk factors should ask a doctor when to begin checking for colorectal cancer, what tests to have, and how often to have them.

Symptoms

Symptoms of colorectal cancer can include: a change in bowel habits or blood in the stools; general abdominal discomfort such as gas pains, bloating or fullness; unexplained weight loss; tiredness and vomiting. These symptoms may be caused by colorectal cancer or by other conditions. It is important to check with a doctor.

Treatment

Treatment of colorectal cancer will vary depending on the tumour size, location and extent of the disease. Several different types of treatment are used to treat colorectal cancer and sometimes different treatments are combined. Options may include surgery to remove the tumour, chemotherapy using anticancer drugs, or radiation therapy using high-energy x-rays to kill cancer cells. Your doctor will work with you to determine the best treatment option.