Cancer of the colon or rectum is often called colorectal cancer. The colon and the rectum are part of the large intestine, which is part of the digestive system. Tumors found in the colon or rectum may be benign (noncancerous) growths of tissue (polyps) or malignant cancerous growths of tissue that may spread to other parts of the body.

Loss of body weight and muscle mass, and weakness that may occur in patients with cancer, AIDS, or other chronic diseases.