Surgery for colon cancer
Surgical therapy for colon cancer usually involves complete resection of the bowel segment containing the tumor with the draining lymph nodes. Depending on the location of the tumor the surgeon may elect to do a left hemicolectoy, transverse colectomy, or a right hemicolectomy. Tumors in the sigmoid colon area are usually treated with wide sigmoid resection.
Surgery for rectal cancer
Preservation of the anal spincter is a major issue in deciding on the surgical treatment options in rectal cancer. The surgeon will like to have at least 2 cm clear margin between the outermost limit of the tumor and the surgical margin. In patients who has rectal cancer located in the upper part of the rectum, it may be possible to preserve the anal spincter, but if the tumor is located in the lower part of the rectum clear resection of the tumor may include the anal spincter. If the anal spincter can not be preserved, the surgeon will do a colostomy (diversion of large bowel to the abdominal wall). The surgery again as in the case of colon cancer will aim at removal of all the draining lymph nodes.