The width of resection margin is still a matter of debate in case of colorectal liver metastasis resection. The aim of this study was to determine the risk factors for R1 resection. Once risk factors had been identified, patients were matched according to Fong\’s prognostic criteria, in order to evaluate whether R1 resection still remained a negative prognostic factor impacting overall and disease-free survival.
A total of 1784 hepatectomies were analyzed from a multicentric retrospective cohort of hepatectomies. Patients were compared before and after a 1:1 propensity score analysis in order to compare R0 versus R1 resections according to Fong criteria.
Primary tumor nodes found positive after colorectal resection (RR = 1.20, p = 0.02), operative time (> 240 min) (RR = 1.26, p = 0.05), synchronous liver metastasis (RR = 1.27, p = 0.02), pedicle clamping (> 40 min) (RR = 1.52, p = 0.001), lesion size larger than 50 mm (RR = 1.54, p = 0.001), rehepatectomy (RR = 1.68, p = 0.001), more than 3 lesions (RR = 1.69, p = 0.0001), and bilateral lesions (RR = 1.74, p = 0.0001) were identified as risk factors in multivariate analysis. After a 1:1 PSM according to Fong criteria, R1 resection still remained a negative prognostic factor impacting overall and disease-free survival, with 1-, 3-, 5-year OS at 94, 81, and 70% in R0 and 92, 75, and 58% in R1, respectively, (p = 0.008), and disease-free survival (DFS) with 1-, 3-, 5-year survival at 64, 41, and 28% in R0 versus 51, 28, and 18% in R1 (p = 0.0002), respectively.
Even after using PSM as an oncological prognostic criterion, R1 resection still impacts overall and disease-free survival negatively.