Robotic-assisted colectomy for right-sided colon cancer: Short-term surgical outcomes of a multi-institutional prospective cohort study in Japan.

Background:In Japan, there are no substantial reports on robotic-assisted colectomy because few institutions performed the procedure, as it was not covered by national insurance until March 2022. Aim:This study aimed to evaluate the safety and feasibility of robotic-assisted colectomy for patients with curatively resectable colon cancer in Japan. Methods:This multi-institutional, prospective, single-arm, observational study enrolled patients diagnosed with curatively resectable clinical stage I-IIIC colon adenocarcinoma with D2 or D3 lymph node dissection and treated with robotic-assisted colectomy. The primary endpoint was the conversion rate to laparotomy. The non-inferiority of outcomes for robotic-assisted colectomy versus laparoscopic colectomy, which was determined from historical data, was verified. Results:One hundred patients were registered between July 2019 and March 2022 and underwent robotic-assisted colectomy performed by seven expert surgeons at six institutions. Thirteen patients were excluded because their surgeons had insufficient experience performing robotic-assisted colectomy; therefore, 87 patients were eligible for the primary endpoint analysis. There was no conversion in these 87 patients, and robotic-assisted colectomy was non-inferior to laparoscopic colectomy in terms of conversion rate (90% confidence interval 0-3.38, p = 0.0006). No intraoperative adverse events occurred, and no mortality was observed in a total of 100 patients. The rate of patients with Clavien-Dindo complications grade III or higher was 4%. Conclusion:This study showed the non-inferiority of the conversion rates between robotic-assisted colectomy and laparoscopic colectomy. Favorable perioperative outcomes also suggest the safety and feasibility of robotic-assisted colectomy.