Sphincter-preserving operations for rectal cancer.

Sphincter-preserving operations represent an important model for integrating the goals of surgery for rectal cancers. These goals--the achievement of cure and local control and the preservation of autonomic visceral pelvic functions--are inherently related. Sphincter-preserving procedures are possible for patients with mid-rectal cancers (6 to 10 cm from the anal verge) and for highly selected patients with distal rectal cancers (< or = 5 cm from the anal verge). Total mesorectal excision, a new concept in resection with negative circumferential margins, dramatically enhances both cure and local control. Total mesorectal excision can be combined with sphincter preservation. Perioperative adjuvant therapy protocols have been combined with sphincter-preserving operations in many investigative settings. Functional outcomes and recent survival data seem to favor preoperative over postoperative radiation therapy. The currently changing standards of surgery for rectal cancer, which result in improved local control, should enhance long-term sphincter preservation in the future.