To Örebro University

Introduction: In rectal cancer minimally invasive surgery (MIS) is recommended with either robotic-assisted or laparoscopic technique. Randomized controlled studies have shown similar outcomes between the techniques. This study aimed to compare population-based data on short-term outcomes between robotic-assisted and laparoscopic surgery for rectal cancer.

Method: Data from the Swedish Colorectal Cancer Registry for patients undergoing MIS for rectal cancer between 2014-2021 with 30-day follow-up were analysed. Primary outcome was positive circumferential resection margin (CRM+). Secondary outcomes were conversion to open surgery, total mesorectal excision (TME) specimen quality and overall or surgical complications. Analyses were conducted by intention-to-treat, with data grouped according to surgical technique. Multivariable analyses were performed.

Result: A total of 5874 patients were analysed (3578 robotic-assisted; 2296 laparoscopic). There was no difference in CRM+ between the groups (6.5 versus 5.9 per cent; P=0.291). Increased rates of conversion were found in the laparoscopic group (16.1 versus 9.1 per cent; P<0.001) and of incomplete TME specimen (4.9 versus 2.7 per cent; P=0.04) and surgical complications (21.5 versus 19.3 per cent; P=0.044) in the robotic-assisted group. In multivariable analysis (Table 1), neither of the techniques was an independent predictor of CRM+ (Odds ratio (OR) 0.99, 95 per cent c.i. 0.75 to 1.30; P=0.925). For secondary outcomes laparoscopic technique was a predictor of conversion (P<0.001) and robotic-assisted of incomplete TME specimen (P<0.001).

Discussion: This population-based study could not show superiority regarding short-term outcomes of any of MIS techniques. Findings regarding conversion rates and incomplete TME specimen warrant further investigation.