Colorectal cancer is the second leading cause of cancer death in the world, and it is also one of the most preventable and manageable diseases. The average person has a 6 percent lifetime chance of developing colorectal cancer. Fourteen percent of cancers diagnosed each year occur in the colon or rectum. Colorectal cancer can occur at all ages, but 90 percent of patients are over the age of 40. The risk of developing cancer increases with age, with most patients being diagnosed in their 50s and 60s. Risk factors include a history of breast, uterine or ovarian cancer, inflammatory bowel disease (ulcerative or clonal colitis), a family history of colorectal polyps or cancer. Most colorectal cancers develop from a single cell or group of cells in the intestine. These cells begin to differentiate and grow into non-cancerous (benign) bulky organisms called polyps. When these polyps get larger, they may become cancerous, infiltrating the bowel wall or metastasizing to other parts of the body. Many colorectal polyps and tumors are asymptomatic until they become quite large, and it is important to detect a tumor when it is not yet large or active. Therefore, screening for people without symptoms will allow early detection of these bulky growths or polyps. Even if you do not have risk factors present, you should have annual anal examinations and fecal occult blood tests starting at age 40. sigmoidoscopy of the lower intestine should be performed starting at age 50. If the physical examination is normal, it needs to be repeated every five years. People with general risk factors should be examined with a barium enema every 5 to 10 years or a colonoscopy every 10 years. People at high risk for colorectal cancer should have the entire colon and rectum examined. Colonoscopy is the best method, but sometimes a barium enema with a bendable sigmoidoscope is sufficient. In general, a review is needed every 5 years. The timing of the first exam depends on risk factors. If there is more than one person in the family with colorectal cancer before age 50, screening should be started at age 40. If one parent has a familial multiple polyp, screening should begin at age 12 to 14. Those with a family history of colorectal cancer or polyps, or a personal history of colorectal cancer or adenomatous polyps, should have a colonoscopy. Any polyps should be removed and rechecked every 1 to 3 years. If the test is normal, a colonoscopy should be done once every 3 to 5 years. Women with breast, ovarian or uterine cancer should have a colonoscopy every 3 to 5 years starting at age 40.