Sphincter preservation therapy for rectal cancer.

Rectal cancer presents a unique challenge to oncologists and patients due to the location and anatomy of the rectum and the difficulties inherent in pre-operative staging. These issues are especially important with distal rectal tumors when patients may face the decision of tumor control without sphincter preservation or more limited surgical procedures that may potentially compromise tumor control and thus survival. Current options for sphincter preservation for low-lying rectal tumors are preoperative radiotherapy with or without chemotherapy for tumor downstaging, local excision with or without adjuvant chemoradiation and low anterior resection with coloanal anastomosis. Pretreatment evaluation, by radiologic studies and pathologic predictors of lymph node involvement, is an integral part of determining which patients are suitable candidates for treatment with local excision. Preoperative chemoradiotherapy is a treatment option for some patients who are not initially considered to be candidates for sphincter preservation. Many investigators have suggested that the rate of sphincter preservation in patients with rectal cancer may be improved following preoperative chemotherapy and radiation. For properly selected patients, local excision holds promise as a means of achieving sphincter preservation.