Cancer of the colon (large intestine or large bowel) or rectum is also called colorectal cancer. It is a disease in which cells in the colon or rectum become abnormal, do not have normal control, and form a mass or tumor. Cancer cells invade and destroy the tissue in or around the tumor, break away from the tumor, and spread to form new tumors in the colon or in other parts of the body. Colorectal cancer is basically preventable with regular screening tests. It is more common in people over 50, and the risk increases with age. That’s why everyone who is 50 years of age or older should be screened for colorectal cancer at the recommended intervals. When polyps and small cancers of the colon are found and removed early, that often prevents or cures colorectal cancer. Much additional information on colorectal cancer, including risk factors for prevention, signs and symptoms, screening tests to help make a diagnosis, and treatment, is provided in our Section on Cancer. Much additional information can also be obtained from the American Cancer Society and the National Cancer Institute. Both of their web sites are just One Click Away on Health Power’s Relevant Resources Table.