Surgery State-of-the-art treatment for localized rectal cancer involves removing the tumor
with at least 3/4 in. (2 cm) of normal tissue on either side of it as well as the regional lymph nodes . The surgeon and the surgical pathologist should examine the rectal margins in the surgical specimen for the presence or absence of tumor. If the tumor is small, it may be removed with a local wedge resection .
In some patients with a tumor that is low in the rectum, high-dose radiation given before the operation may reduce the size of the tumor, allowing it to be removed while still leaving enough bowel below the tumor site for the surgeon to sew the bowel back together. This will spare the rectum and the sphincter muscle, thereby avoiding the need for a colostomy in up to 85 percent of patients with rectal cancer.
Mortality for this operation is less than 7 percent, but there is a 25 to 40 percent incidence of impotence or urologic problems. About 10 to 15 percent of patients have a late local recurrence of cancer in the pelvis, particularly when sphincter-preserving operations have been used for low-lying tumors.
But the main concern should be removing all the tumor and a reasonable margin on either side—which leads to cure—rather than preserving the sphincter.
In rare cases of non-invasive tumors— those confined to the top layers of the rectal lining (mucosa and submucosa)—it is sometimes possible to remove the tumor from below, entering through the anus and using a
