Sphincter Preservation in Low Rectal Cancer is Facilitated by Preoperative Chemoradiation and Intersphincteric Dissection

Objective: The aim of this study was to evaluate oncologic outcome in patients with locally advanced distal rectal cancer treated with preoperative chemoradiation followed by low anterior resection (LAR)/stapled coloanal anastomosis, LAR/intersphincteric dissection/hand-sewn coloanal anastomosis, or abdominoperineal resection (APR). Summary Background Data: Distal rectal cancer presents a surgical challenge, and the goals of treatment often include tumor eradication without sacrifice of the anal sphincters. The technique of intersphincteric resection removes the internal anal sphincter to gain additional distal rectal margin in hopes of avoiding a permanent stoma. Methods: We analyzed 148 patients with stage II and III rectal cancers (endorectal ultrasound staged uT3-4 and/or uN1) located <= 6 cm from the anal verge, treated by preoperative chemoradiation and total mesorectal excision from 1998 to 2004. Eighty-five patients (57%) had sphincter-preserving resection (41, LAR/stapled coloanal anastomosis; 44, LAR/intersphincteric resection/hand-sewn coloanal anastomosis); 63 patients had APR. Results: Patients undergoing APR were older, with more poorly differentiated tumors evidencing less response to chemoradiation and more likely to require extended resection. Complete resection with negative histologic margins was achieved in 92%; circumferential margins were positive in 2 (5%) of 44 in the intersphincteric resection group and 8 (13%) of 63 in the APR group. Distal margins were positive in 2 (5%) of 44 in the intersphincteric resection group. With median follow-up of 47 months, there were a total of 7 local recurrences (5%): 1, 0, and 6 in the stapled anastomosis, intersphincteric resection, and APR groups, respectively. Estimated 5-year recurrence-free survival for the stapled anastomosis, intersphincteric resection, and APR groups were 85%, 83%, and 47% respectively (P = 0.001). Conclusions: In low rectal cancer, sphincter preservation is facilitated by a significant response to preoperative chemoradiation and intersphincteric resection, without compromise of margins or outcome. In those who have a less favorable response, abdominoperineal resection is more likely to be required and is associated with poorer Outcome.