Acceptance of sphincter-preserving surgery for T3 lower rectal cancer after short-course radiotherapy with delayed surgery.

Abstract

620 Background: One of the reasons for avoiding sphincter-preserving surgery for lower rectal cancer is difficulty in obtaining a sufficient distal margin. Short-course radiotherapy (SRT) with immediate surgery is not expected to reduce tumor volume, and currently available evidence suggests that it does not increase the sphincter-preservation rate. However, SRT with delayed surgery has been linked to downsizing of the primary tumor during the waiting period. We evaluated the feasibility of sphincter-preserving surgery for T3 lower rectal cancer after SRT with delayed surgery and examined whether a distal margin of ≤ 5 mm has an impact on oncologic outcomes. Methods: We retrospectively studied 161 consecutive patients with lower rectal cancer located below the peritoneum reflection who underwent radical surgery with total mesorectum resection (TME) 3 to 4 weeks after the completion of SRT. The median follow-up was 53.5 months. Results: Sphincter-preserving surgery was performed in 149 (92.5%) of the 161 patients. The procedures were as follows: double-stapling technique, 58 patients; intersphincteric resection, 91; abdominoperineal resection, 10; and Hartmann operation, 2. Among the patients who underwent sphincter-preserving surgery, the distal margin was ≤ 5 mm in 41 patients and > 5 mm in 108. The local recurrence rate was respectively 5.8% vs. 10.4% (p = 0.606), the recurrence-free survival 83.4% vs. 82.8% (p = 0.682), and the overall survival at 5 years 82.3% vs. 87.6% (p = 0.418). Our results suggested that there is no difference in long-term outcomes between a distal margin of ≤ 5 mm and > 5 mm. Conclusions: Sphincter-preserving surgery was performed in 92.5% of patients with T3 lower rectal cancer who received SRT with delayed surgery. Our results confirmed the long-term oncologic feasibility of sphincter-preserving surgery with a distal margin of ≤ 5 mm; there was no negative impact on long-term outcomes such as local recurrence, recurrence-free survival, and overall survival.