Impact of the width of resection margin from colorectal liver metastasis on post-operative survival and recurrence

Abstract

Background: Treatment for colorectal liver metastasis (CRLM) involves sparing liver parenchyma surgical techniques. Hence, the impact of subcentimetric resection margins (RM) needs to be investigated. Methods: 682 patients were analysed from 2005 to 2015. They were allocated in four groups according with the width of RM: <1 mm (R1 resection), ≥1mm-4mm, 5-9mm and ≥10mm. Results: Survival rate was 66.3% in a follow up period of 20.58 months. Survival rates (p=0.027) and overall survival (p=0.001) increased steadily with the increment of width in RM. The disease and liver recurrence rates were 57.3% and 36.1%, respectively, both higher for groups with narrower RM (p<0.001). R1 resection was an independent risk factor for mortality (HR:23.73; p=0.008), hepatic recurrence (HR:1.265; p=0.015) and R0 resection protective for disease recurrence (HR:0.836; p=0.009). Lack of adjuvant chemotherapy following CRLM resection was a risk factor for hepatic (HR:1.229; p=0.003) and disease recurrence (HR:1.143; p=0.013). Although, adjuvant chemotherapy isolated was a protective factor for mortality (HR:0.276; p=0.004) in synchronous presentation, this was not significant for the subgroup with R1 resection (p=0.392) or metachronous disease. Conclusion: Survival and recurrence were progressively affected with larger subcentimetric histological margins. Adjuvant chemotherapy brought benefits but not for all subgroups, reinforcing the importance of a histologically free RM and a target of 10mm, even in the era of modern treatments.