Using the win ratio to compare laparoscopic versus open liver resection for colorectal cancer liver metastases

Background: We sought to assess the overall benefit of laparoscopic versus open hepatectomy for treatment of colorectal liver metastases (CRLM) using the win ratio, a novel methodological approach. Methods: CRLM patients undergoing curative-intent resection in 2001-2018 were identified from an international multi-institutional database. Patients were paired and matched based on age, number and size of lesions, lymph node status and receipt of preoperative chemotherapy. The win ratio was calculated based on margin status, severity of postoperative complications, 90-day mortality, time to recurrence, and time to death. Results: Among 962 patients, the majority underwent open hepatectomy (n=832, 86.5%), while a minority underwent laparoscopic hepatectomy (n=130, 13.5%). Among matched patient-to-patient pairs, the odds of the patient undergoing laparoscopic resection "winning" were 1.77 (WR 1.77, 95% CI: 1.42-2.34). The win ratio favored laparoscopic hepatectomy independent of low (WR 2.94, 95% CI: 1.20-6.39), medium (WR 1.56, 95% CI: 1.16-2.10) or high (WR 7.25, 95% CI: 1.13-32.0) tumor burden, as well as unilobar (WR 1.71, 95% CI: 1.25-2.31) or bilobar (WR 4.57, 95% CI: 2.36-8.64) disease. The odds of "winning" were particularly pronounced relative to short-term outcomes (i.e., 90-day mortality and severity of postoperative complications) (WR 4.06, 95% CI: 2.33-7.78). Conclusions: Patients undergoing laparoscopic hepatectomy had 77% increased odds of "winning". Laparoscopic liver resection should be strongly considered as a preferred approach to resection in CRLM patients.