[Clinical advantages of robotic surgery in low rectal cancer:a post-hoc analysis of the REAL study]

Objectives: To compare the risk of anastomotic leak following robotic-assisted and laparoscopic surgery in patients with mid-low rectal cancer,and to investigate the independent risk factors associated with each surgical approach. Methods: This study is a post-hoc analysis of a multicenter randomized controlled trial (REAL study). A total of 689 patients with mid-low rectal cancer who underwent robotic or laparoscopic sphincter-preserving surgery without prophylactic stoma at 11 medical centers in China from July 2016 to December 2020 were enrolled in this study. There were 396 males and 293 females, with an age of (59.6±10.8) years (range: 18 to 80 years). Patients were divided into the robotic surgery group (359 cases) and the laparoscopic surgery group (330 cases) according to the surgical approach. Univariate and multivariate Logistic regression models were used to analyze the risk factors for anastomotic leak after each surgical technique,and the interaction effect between tumor location and surgical approach was evaluated. Results: Anastomotic leakage occurred postoperatively in 23 patients (6.5%) in the robotic surgery group and 34 patients (10.3%) in the laparoscopic surgery group, with no statistically significant difference between the two groups (χ²=2.949, P=0.088). Univariate and multivariate analysis results showed that low rectal cancer (≤5 cm) and mid-low rectal cancer (>5 to 7 cm) were independent risk factors for anastomotic leakage after laparoscopic surgery (OR=5.102, P=0.006; OR=4.019, P=0.015); the degree of tumor differentiation was an independent risk factor for anastomotic leakage after robotic-assisted mid-low rectal cancer surgery (OR=2.649, 95%CI: 1.037 to 6.891, P=0.042). Interaction analysis revealed that the lower the location of the rectal tumor, the higher the risk of anastomotic leakage after laparoscopic surgery, reaching 5.306 times that of robotic-assisted surgery (OR=5.306, 95%CI: 2.336 to 12.048, P<0.01). Conclusions: Robotic-assisted surgery can reduce the risk of postoperative anastomotic leakage in patients with low rectal cancer. Tumor location is a risk factor for anastomotic leakage after laparoscopic surgery.