Operative safety and oncologic outcomes of anal sphincter-preserving surgery with mesorectal excision for rectal cancer: 931 consecutive patients treated at a single institution

Background: This study was designed to evaluate the operative safety and long-term oncologic outcomes of sphincter-preserving surgery based on sharp mesorectal excision for rectal cancer. Methods: Between January 1989 and June 2004, 931 patients underwent sphincter-preserving surgery based on sharp mesorectal excision. The operative safety and oncologic outcomes were assessed for the periods of 1989-1996 (n = 208) and 1997-2004 (n = 723). Total mesorectal excision (TME)-based sphincter-preserving surgery was performed during the period of 1989-1996. A multidisciplinary team approach and tailored mesorectal excision, which is the differential removal of the mesorectum, were our standard treatment for patients with rectal cancer during the period of 1997-2004. Results: The use of preoperative chemoradiation (P < 0.001), ultralow anterior resection with coloanal anastomosis (P = 0.01), diverting stoma (P = 0.001), and <2 cm of a distal resection margin (P = 0.01) were more common during the period of 1997-2004. There were no differences between the two periods with regard to perioperative complications (P = 0.2), such as anastomosis leakage (2.4% vs. 3.6%). Cancer-specific survival rates (79.1% vs. 79.6%, P = 0.7) and local recurrence (8.4% vs. 8.6%, P = 0.99) did not differ significantly for the two periods. Conclusions: Based on sharp mesorectal excision, operative safety and oncologic outcomes were not compromised by technical advances in sphincter-preserving surgery using tailored mesorectal excision and a shortened distal margin.