Surgical removal of the distal colon (part of the large bowel), rectum, and anal sphincter complex using both anterior abdominal and perineal incisions. A permanent colostomy / stoma is formed (the end of the bowel is brought to the surface of the left abdomen). It has been developed more than 100 years ago, and it remains an important tool in the treatment of rectal cancer. However, with surgical advances, the operation may be carried out with keyhole surgery, and the anal sphincter may be preserved.