Proficient surgeons enhance conversion rates and sphincter preservation in robotic rectal cancer surgery with comparable long-term outcomes: a comparative study with laparoscopy in a large-volume center in China.

Background: Despite theoretical advantages, skepticism persists about robotic rectal cancer surgery due to the lack of evidence of benefit. This study aims to compare oncological and functional results of robotic-assisted surgery to laparoscopy, focusing on proficient surgeons with expertise in both techniques.

Methods: This retrospective study reviewed and compared 1304 patients who underwent either robotic surgery (n = 295) or laparoscopic surgery (n = 1009) for rectal cancer. The surgical procedures were performed by a team of highly skilled surgeons who individually carry out more than 350 laparoscopic or robotic colorectal cancer surgeries over the course of their career. Perioperative outcomes, recurrence data, and intestinal function outcomes were compared between groups with a propensity score matching (PSM) method. The primary outcomes were sphincter preservation and conversion to open laparotomy. Secondary endpoints included 3-year disease-free survival (DFS), 3-year overall survival (OS), complications, and the occurrence of low anterior resection syndrome (LARS). Fisher's exact test and χ2 were used to compare discrete variables between groups, while parametric (t-test) and nonparametric (U test, Kruskal-Wallis) tests were used for continuous outcomes, as appropriate. The Kaplan-Meier and log-rank tests were employed to analyze and compare the DFS and OS outcomes.

Results: The patients in the robotic group were younger, with a higher cN stage, positive EMVI and CRM, and a lower tumor location compared to the patients in the laparoscopic group. The robotic group also had more neoadjuvant chemoradiotherapy, causing an imbalance in (y)pT and (y)pN stage. Following PSM, all covariates were effectively balanced between the two groups. The robotic group had significantly higher sphincter preservation rates (94.0% vs. 84.4%, P < 0.001) and no conversions to open laparotomy, while the laparoscopic group had 7 cases (0 vs. 2.5%, P = 0.015). There were no significant differences observed in diverting ileostomy, operative time, estimated blood loss, complications, margin involvement, or duration of hospitalization. The median follow-up was 31 months. No significant differences were found between the robotic and laparoscopic groups in terms of 3-year OS (94.1% vs. 93.3%, P = 0.812) and DFS (85.9% vs. 84.7%, P = 0.797). The robotic group had similar rates of recurrence in various sites, including local, liver, lung, bone, and peritoneal metastases. Major LARS occurred in 11.3% of patients, while minor LARS occurred in 14.8% with no significant differences between the groups (P = 0.54).

Conclusion: Comparable complication rates, 3-year OS, and DFS were found between robotic and laparoscopic rectal cancer surgery. Furthermore, it shed light on supplementary benefits associated with this approach, such as decreased conversion rates and enhanced sphincter preservation, particularly when performed by skilled surgeons in specialized, high-volume medical facilities.