For cancer in the descending colon, a left-sided hemicolectomy and a standard bowel- and lymph node resection are performed. The bowel is divided to the left on the transverse colon and upwards on the rectum. The distal sigmoid colon is not being retained because the blood supply may not remain satisfactory.
The inferior mesenteric veins are divided centrally. (The artery at the aorta and the vein close to the edge of the pancreas.)