The impact of margins on outcome after hepatic resection for colorectal metastasis

Hepatic resection is the only treatment modality associated with long-term survival in patients with colorectal liver metastasis. Five-year survival rates ranging from 25% to 58% have been reported with hepatic resection.1–3 With improved surgical techniques and chemotherapy, more patients are subjected to resection, including patients previously considered unresectable. Several clinicopathologic factors have been analyzed and are now considered to be independent prognostic factors associated with survival.4–13 The role of resection margin status as a prognostic factor to predict survival after hepatic resection for colorectal metastasis is controversial. In addition, the optimal margin width, if any, is unclear. Early documentation by some reports of a potential benefit associated with a 1-cm margin led to the general acceptance of this margin width to guide hepatic resections.14 Since that time, several studies addressing the issue of margin width have yielded conflicting results. Some authors have shown that a margin width >1 cm is associated with improved survival when compared with subcentimeter resections.4,15–19 In contrast, other reports have documented that the margin width does not have any effect on survival as long as it is negative,2,20,21 whereas some studies have noted that although a >1 cm margin is desirable, survival is not influenced by the width of the subcentimeter margin (0–9 mm).3,22 Firm conclusions from these studies are limited by small numbers of patients and limited statistical power. The only reports with a large number of patients were multi-institutional studies,2,7,11 in which institutional differences in the method of liver transection and pathologic analysis of the margin may confound the results. From these conflicting studies, the prognostic significance of margin status and the optimal margin width remain unclear. This is all the more important, since an increasing number of complex resections are performed in which the extent of hepatic involvement frequently mandates close resection margins. The aim of this study was to determine the impact of margin width on long-term survival after hepatic resection for colorectal metastasis in a large, consecutive series of patients from a single institution. Second, the study hopes to determine the influence of margin width on survival in the context of well-established clinicopathologic prognostic factors.