A colectomy is a surgical procedure used to treat colon diseases, such as cancer, inflammatory diseases and diverticulitis. During a colectomy, a portion of the colon is removed and the remaining intestines are connected back to each other or to a stoma to form a colostomy (an opening from the intestines to the outside of the body). This procedure can be done through a traditional open procedure, or laparoscopically with a few small incisions. A colectomy is commonly chosen to treat cancer in the early stages, though it can be successful in treating a more advanced cancer. You may need to stay in the hospital for up to seven days after the procedure.