No beneficial effect on survival but a decrease in postoperative complications in patients with rectal cancer undergoing robotic surgery: a retrospective cohort study

Background Robotic surgery has been taken as a new modality to surpass the technical limitations of conventional surgery. Here we aim to compare the oncologic outcomes of patients with rectal cancer receiving robotic vs. laparoscopic surgery. Methods Data from patients diagnosed with rectal cancer between March 2011 and December 2018 were obtained for outcome assessment at the First Affiliated Hospital of Nanchang University. All patients were separated into two groups: a robot group (patients receiving robotic surgery, n = 314) and a laparoscopy group (patients receiving laparoscopic surgery, n = 220). The primary endpoint was survival outcomes. The secondary endpoints were the general conditions of the operation, postoperative complications and pathological characteristics. Results The 5-year overall survival (OS) and disease-free survival (DFS) at years 1, 3 and 5 were 96.6%, 88.7%, and 87.7% vs. 96.7%, 88.1%, and 78.4%, and 98.6%, 80.2-, and 73.5% vs. 96.2-, 87.2-, and 81.1% in the robot and laparoscopy groups, respectively (P > 0.05). In the multivariable-adjusted analysis, robotic surgery was not an independent prognostic factor for OS and DFS (P = 0.925 and 0.451, respectively). With respect to the general conditions of the operation, patients in the robot group had significantly shorter operation times (163.5 +/- 40.9 vs. 190.5 +/- 51.9 min), shorter times to 1(st) gas passing [2(1) vs. 3(1)d] and shorter hospital stay days [7(2) vs. 8(3)d] compared to those in the laparoscopy group (P < 0.01, respectively). After the operation, the incidence of short- and long-term complications in the robot group was significantly lower than that in the laparoscopy group (15.9% vs. 32.3%; P < 0.001), especially for urinary retention (1.9% vs. 7.3%; 0.6% vs. 4.1%, P < 0.05, respectively). With regard to pathological characteristics, TNM stages II and III were more frequently observed in the robot group than in the laparoscopy group (94.3% vs. 83.2%, P < 0.001). No significant difference were observed in lymph nodes retrieved, lymphovascular invasion and circumferential resection margin involvement between the two groups (P > 0.05, respectively). Conclusions This monocentre retrospective comparative cohort study revealed short-term advantages of robot-assisted rectal cancer resection but similar survival compared to conventional laparoscopy.