Use of detailed pathologic characteristics of the primary colorectal tumor to predict outcome after hepatectomy for metastases.

Abstract

559 Background: Outcome after hepatic resection for colorectal liver metastases (CRLM) is heterogeneous and accurate predictors of survival are lacking. The aim of our study was to analyze the prognostic relevance of pathologic details of the colorectal primary tumor in patients undergoing hepatic resection of CRLM. Methods: Retrospective review of a prospective database identified patients who underwent potentially curative hepatic resection of CRLM. Clinicopathological variables were investigated and their association with outcome was analyzed. Results: From 1997-2007, 1004 patients underwent hepatic resection for CRLM. The median follow-up for survivors was 59 months with a 5-year predicted survival of 47%. Ninety-two percent of patients received perioperative chemotherapy and 34% received adjuvant hepatic artery infusion chemotherapy. Univariate analysis identified 10 factors associated with poor survival. Three of these related to the pathology of the primary tumor: lymphovascular invasion (LVI, p<0.0001), perineural invasion (p=0.005), and degree of regional lymph node involvement (N0 vs N1 vs N2, p<0.0001). Multivariate analysis identified 7 factors associated with poor survival. Two of these related to the pathology of the primary tumor: LVI (HR 1.3, 95% CI 1.06-1.64, p=0.01) and degree of regional lymph node involvement where an increase in the number of metastatic regional lymph nodes from N1 (HR 1.3, 95% CI 1.04-1.69, p=0.02) to N2 (HR 1.7, 95% CI 1.27-2.21, p <0.0005) was associated with a reduced survival. LVI positive patients had a median survival of 48 months compared to 69 months for LVI negative patients (p<0.0001); moreover, patients who were LVI positive with N2 nodal disease had a reduced survival to 40 months compared to 74 months for patients who were LVI negative with no nodal disease (p<0.0001). Conclusions: Resection of CLRM is associated with long-term survival. Pathologic details of the primary colorectal tumor, particularly LVI and the degree of lymph node involvement, are strong predictors of survival. Future biomarker studies should consider utilizing factors related to the primary colorectal tumor.