By Michael Vlessides

LONG BEACH, Calif.—A real-world study has concluded that robotic surgery significantly improves three-year relapse-free survival compared with laparoscopic surgery in patients with rectal cancer. Of interest, the investigation found that robotic surgery offered limited benefit in patients 80 years of age and older.

“Robotic surgery offers several advantages over laparoscopic surgery in rectal cancer, and is being increasingly used for these procedures around the world,” began Ryosuke Mizuno, MD, a surgeon in the Graduate School of Medicine at Kyoto University, in Japan. “Although many studies have reported in improvements in short-term outcomes with robotic surgery in these patients, a clear superiority has not been shown in long-term outcomes.”

To help clarify this relationship, Dr. Mizuno and his colleagues enrolled 1,053 adult patients into the multicenter cohort study, all of whom had been diagnosed with clinical stage I to III middle and low rectal adenocarcinoma and subsequently underwent elective robotic or laparoscopic surgery. The primary outcome was three-year relapse-free survival. Secondary end points included postoperative complication rate, three-year overall survival, complete resection rate and anastomotic leakage rate.

Presenting at the 2025 annual meeting of the Society of American Gastrointestinal and Endoscopic Surgeons, Dr. Mizuno reported that 536 patients underwent robotic surgery and 517 laparoscopic surgery. It was found that the average operative time was 435 minutes in the robotic group, significantly longer than the 366 minutes among patients undergoing laparoscopic surgery.

Three-year relapse-free survival was significantly higher in the robotic group (83.6% vs. 78.2%; hazard ratio [HR], 0.72; 95% CI, 0.52-0.99). Pathologic complete resection rate was also significantly better in robotic surgery patients (98.2% vs. 95.4%; risk ratio [RR], 0.39; 95% CI, 0.16-0.91).

Analyses of other surgical and postoperative outcomes found that blood loss was statistically comparable between groups. Anastomotic leakage, on the other hand, occurred in 5.6% of the robotic surgery patients and 4.0% of those who underwent laparoscopic surgery (RR ,1.39; 95% CI, 0.76-2.54). Conversely, the rate of any complication (Clavien-Dindo grade II or greater) was 28.4% in the robotic surgery patients and 32.0% in those who underwent laparoscopic surgery (RR, 0.89; 95% CI, 0.72-1.09).

“In terms of our secondary outcomes, robotic surgery also had a better trend in three-year overall survival [94.4% vs. 90.6%] and a lower local recurrence rate [4.6% vs. 6.4%],” Dr. Mizuno noted. Liver, lung and peritoneal recurrence were all lower in patients undergoing robotic surgery.

The researchers also performed a series of subgroup analyses, which indicated more favorable outcomes with robotic surgery in men (HR, 0.71; 95% CI, 0.48-1.05) as well as in patients with cT4 tumors (HR, 0.53; 95% CI, 0.24-1.14). Conversely, the HR in patients older than 80 years of age was found to be 1.04 (95% CI, 0.52-2.08) with robotic surgery.

These findings, the researchers said, demonstrate that beneficial real-world effects of robotic surgery on three-year relapse-free survival compared with laparoscopic surgery. “Several studies have been shown trends toward better long-term outcomes with robotic surgery,” Dr. Mizuno concluded. “Many studies have reported three-year relapse-free survival rates between 80% and 94% with robotic surgery. Our study was consistent with these findings.”

But as Dr. Mizuno explained, the potential lack of efficacy of robotic surgery in older adults proved puzzling. “Robotic surgery in our study was associated with a longer operative time, so there may be adverse effects from prolonged general anesthesia,” he speculated.

Session co-moderator Christopher Schlachta, MD, was surprised by the longer operative times in the robotic surgery group.

“In my practice, I’ve found that doing robotic rectal cancer surgery actually saves time over laparoscopic surgery,” said Dr. Schlachta, a professor of surgery and oncology at Western University Schulich School of Medicine and Dentistry, in London, Ontario. “So why do you think you found that it takes 60 minutes longer? Surely that’s not just docking time.”

“This study included the first steps of robotic surgery in Japan,” Dr. Mizuno replied. “As a result, some hospitals had little experience with robotic surgery, which resulted in the longer operative times.”

 

Drs. Mizuno and Schlachta reported no relevant financial disclosures.