Radiotherapy before or after the operation may decrease the incidence of local pelvic recurrence .
In tumors that are very low in the rectum—within 5 to 6 cm (2 to 2½ in.) of the anus—once the tumor and its lower edge have been removed there is no rectum left to sew back together. In these cases the surgeon performs an abdominal perineal resection , the standard treatment for invasive cancer . The rectum and the anus with all its muscular attachments are removed, leaving the patient with a permanent colostomy ( see Ostomy ).
Ongoing clinical trials are attempting to identify patients who may be spared this extensive surgery. This investigative approach treats selected patients with a local excision of the tumor (as long as the margins show no evidence of cancer), along with radiation to the pelvis and often chemotherapy as well.
A novel stapling device to join the ends of the bowel may sometimes allow the surgeon to perform what is called a low anterior resection in some patients with low rectal cancers. This will also help avoid a colostomy.
Where there is no evidence of gross pelvic disease after local excision with negative margins, adjuvant pelvic radiation may be an alternative to abdominal perineal resection. This may help reduce local recurrence, which is associated with significant symptoms. Follow-up studies are in progress.
Radiation Radiation given before or after surgery has been used to treat rectal cancer. High-dose
preoperative therapy in selected high-risk cases—selection depends on the size and location of the tumor—will improve survival, reduce local recurrence and allow the sphincter to be preserved even in low rectal cancers.
