Robotic surgery enhances patients' survival in rectal cancer: a propensity score-weighted multicenter cohort study.

Background: Although robotic surgery for rectal cancer has demonstrated favorable short-term outcomes, its mid-term benefits remain unclear. Moreover, randomized controlled trials have not evaluated its effectiveness in real-world settings.

Methods: This study included patients diagnosed with stage I-III middle or lower rectal adenocarcinoma who underwent minimally invasive surgery between 2018 and 2021 at 16 hospitals in Japan. The inverse probability of treatment weighting method based on propensity score was used to adjust for confounding factors. The primary outcome was the 3-year relapse-free survival (RFS).

Results: Of the 1053 patients, 536 underwent robotic surgery and 517 underwent laparoscopic surgery. The mean operative time was longer in the robotic group (robotic: 435 min vs. laparoscopic: 366 min). No significant difference was observed in Clavien-Dindo Grade II or higher any complications (robotic: 28.4% vs. laparoscopic: 32.0%, risk ratio [RR] 0.89, 95% confidence interval [CI]: 0.72-1.09). The rate of pathological complete resection was significantly higher in the robotic group (robotic: 98.2% vs. laparoscopic: 95.3%, RR 1.03, 95% CI 1.00-1.06). The 3-year RFS was significantly better in the robotic group (robotic: 83.6% vs. laparoscopic: 78.2%, hazard ratio [HR] 0.72, 95% CI: 0.53-0.99), and the 3-year overall survival also showed a favorable trend in the robotic group (robotic: 94.4% vs. laparoscopic: 90.6%; HR 0.60, 95% CI 0.35-1.03). Subgroup analysis indicated that robotic surgery for rectal cancer may be more effective in male patients or those with T4 tumors.

Conclusion: Robotic surgery for rectal cancer may be associated with a higher complete resection rate and improved 3-year RFS compared with conventional laparoscopic surgery in a real-world setting.