Colectomy It is a surgical procedure to remove all or a part of the colon. If only a part of the colon is removed, then it is called a partial colectomy. This procedure is also known as a bowel surgery. The colon is part of the human body's digestive system. The digestive system removes and processes nutrients from foods and helps waste materials to come out of the body. Colectomy is used to treat and prevent diseases that affect the colon, such as: Bleeding that can't be controlled: Severe bleeding from the colon may require surgery to remove the affected portion of the colon. Colon cancer: Early cancer detection may require only a small part of the colon to be removed during surgery. Cancers at a later stage require more of the colon to be removed. Ulcerative colitis: Your doctor may recommend total colectomy if medications aren't helping. Surgery may also be a choice if precancerous changes are found during a colonoscopy. Preventive surgery: If you have a very high risk of getting prone to colon cancer due to multiple precancerous colon polyps, you may choose to undergo total colectomy to prevent cancer in the future.