Colectomy is a surgery to remove all or part of the colon. Nearby lymph nodes are removed as well. Hemicolectomy or partial colectomy is when part of the colon is removed. If the entire colon is removed, it is called a total colectomy. Total colectomy is not often needed to treat colon cancer. It is generally used only if there is disease in the part of the colon without the cancer, such as hundreds of polyps (in familial adenomatous polyposis) or inflammatory bowel disease. The image above shows an open colectomy; the affected section is excised through a single large incision in the abdomen.