Open versus Laparoscopic Surgery for Advanced Low Rectal Cancer: A Large, Multicenter, Propensity Score Matched Cohort Study in Japan

Background: Laparoscopic surgery for rectal cancer is widely performed all over the world and several randomized controlled trials have been reported. However, the usefulness of laparoscopic surgery compared with open surgery has not been demonstrated sufficiently, especially for the low rectal area. Objective: The aim of this study was to investigate the hypothesis that laparoscopic primary tumor resection is safe and effective when compared with the open approach for locally advanced low rectal cancer. Patients and Methods: Data from patients with clinical stage II to III low rectal cancer below the peritoneal reflection were collected and analyzed. The operations were performed from 2010 to 2011. Short-term outcomes and long-term prognosis were analyzed with propensity score matching. Results: Of 1608 cases collated from 69 institutes, 1500 cases were eligible for analysis. The cases were matched into 482 laparoscopic and 482 open cases. The mean height of the tumor from the anal verge was 4.6 cm. Preoperative treatment was performed in 35% of the patients. The conversion rate from laparoscopic to open surgery was 5.2%. Estimated blood loss during laparoscopic surgery was significantly less than that during open surgery (90 vs 625 mL, P < 0.001). Overall, the occurrence of complications after laparoscopic surgeries was less than that after open surgeries (30.3% vs 39.2%, P = 0.005). Three-year overall survival rates were 89.9% [95% confidence interval (95% CI) 86.7-92.4] and 90.4% (95% CI 87.4-92.8) in the laparoscopic and open groups, respectively, and no significant difference was seen between the 2 groups. No significant difference was observed in recurrence-free survival (RFS) between the 2 groups (3-year RFS: 70.9%, 68.4 to 74.2 vs 71.8%, 67.5 to 75.7). Conclusion: Laparoscopic surgery could be considered as a treatment option for advanced, low rectal cancer below the peritoneal reflection, based on the short-term and long-term results of this large cohort study (UMIN-ID: UMIN000013919).