Long-Term Oncologic Outcomes After Laparoscopic Versus Open Resection for Colorectal Liver Metastases A Randomized Trial

Background: Despite the recent worldwide dissemination of laparoscopic liver surgery, no high-level evidence supports the oncologic safety of this approach. Objective: To evaluate long-term oncologic outcomes after laparoscopic versus open liver resection in patients with colorectal metastases. Design: A single-center, assessor-blinded, randomized controlled trial (OSLO-COMET [Oslo Randomized Laparoscopic Versus Open Liver Resection for Colorectal Metastases Trial]). Setting: Oslo University Hospital, the only provider of liver surgery for the 3 million inhabitants of southeastern Norway. Participants: Patients with resectable colorectal liver metastases were randomly assigned to have open or laparoscopic liver resection. Intervention: From February 2012 to January 2016, a total of 280 patients were included in the trial (laparoscopic surgery: n = 133; open surgery: n = 147). Measurements: The primary outcome was postoperative morbidity within 30 days. Five-year rates of overall and recurrence-free survival were predefined secondary end points. Results: At a median follow-up of 70 months, rates of 5-year overall survival were 54% in the laparoscopic group and 55% in the open group (between-group difference, 0.5 percentage point [95% CI, -11.3 to 12.3 percentage points]; hazard ratio, 0.93 [CI, 0.67 to 1.30]; P = 0.67). Rates of 5-year recurrence-free survival were 30% in the laparoscopic group and 36% in the open group (between-group difference, 6.0 percentage points [CI, -6.7 to 18.7 percentage points]; hazard ratio, 1.09 [CI, 0.80 to 1.49]; P = 0.57). Limitation: The trial was not powered to detect differences in secondary end points and was not designed to address a non-inferiority hypothesis for survival outcomes. Conclusion: In this randomized trial of laparoscopic and open liver surgery, no difference in survival outcomes was found between the treatment groups. However, differences in 5-year overall survival up to about 10 percentage points in either direction cannot be excluded. This trial should be followed by pragmatic multicenter trials and international registries.