Colorectal cancer hepatic metastases resection margins outcomes: a single-centre retrospective cohort study

Background:Surgical resection is the most efficient treatment for isolated colorectal cancer hepatic metastases. Among the known prognostic factors of this procedure, the impact of the resection margin width is still a controversial matter in the literature.Methods:A retrospective cohort study was performed including 170 patients who underwent surgical resection of colorectal cancer liver metastases (CRLMs) between 2006 and 2016 in our hepatobiliary unit. Resection margin width was determined histologically by measuring the distance from the tumour in millimetres or centimetres. Patients' clinical characteristics were also collected. Patients were then stratified in two tumour margin groups: below 5 mm (group A) and equal to or above 5 mm (group B). Overall survival (OS) and disease-free survival (DFS) were the primary outcomes.Results:Kaplan-Meier curves showed significantly better outcomes for cases having resection margins above 5 mm for both DFS with 1508.7 days (range 1151.2-1866.2) in group A, compared to 2463.9 days (range 2021.3-2906.5) in group B (P=0.049), and OS with 1557.8 days (range 1276.3-1839.3) for group A and 2303.8 days (range 1921.2--2686.4) for group B (P=0.020). This survival benefit was not significant for patients presenting with stage IV CRC at diagnosis or cases where extended (7+ segments) resections were performed.Conclusion:Five-millimetre margins provide a significant survival advantage and should be aimed for in the treatment of CRLMs. Further research on the cause for this finding, including tumour biology's impact on survival, is required.