The effects of resection margin and KRAS status on outcomes after resection of colorectal liver metastases

BackgroundThe aim of this study was to investigate the influence of resection margin status in patients with KRAS mutations (mt-KRAS) when compared to those with wild-type KRAS (wt-KRAS) on long-term outcomes in patients with resected CRLM.MethodsAll patients who underwent resection of CRLM with curative intent between January 2011 and December 2016 and had a KRAS type recorded were included in the study. Overall survival (OS), as well as death-censored overall (RFS) and liver-specific (LS-RFS) recurrence-free survival between KRAS types and the margin status within KRAS subgroups were compared using Cox regression models.ResultsData were available for N = 500 patients (30.4% mt-KRAS). mt-KRAS status was independently associated with significantly shorter OS. Within the wt-KRAS subgroup, smaller margins were found to be associated with significantly shorter death-censored LS-RFS (p < 0.001), with HRs of 1.93 (p = 0.005) for 1–4 mm margins and 2.83 (p < 0.001) for <1 mm margins, relative to those with clear margins. No such association was observed in the mt-KRAS subgroup (p = 0.721).ConclusionThe resection margin status is of greater importance in patients with wt-KRAS. Such information could be useful in the operative planning, especially for those with multiple metastatic deposits, and also in the post-operative counselling and surveillance based on the margin and KRAS status.