Survival after hepatic resection for metastatic colorectal cancer: trends in outcomes for 1,600 patients during two decades at a single institution.

BACKGROUND This study analyzes factors associated with differences in long-term outcomes after hepatic resection for metastatic colorectal cancer over time. STUDY DESIGN Sixteen-hundred consecutive patients undergoing hepatic resection for metastatic colorectal cancer between 1985 and 2004 were analyzed retrospectively. Patients were grouped into 2 eras according to changes in availability of systemic chemotherapy: era I, 1985 to 1998; era II, 1999 to 2004. RESULTS There were 1,037 patients in era I and 563 in era II. Operative mortality decreased from 2.5% in era I to 1% in era II (p = 0.04). There were no differences in age, Clinical Risk Score, or number of hepatic metastases between the 2 groups; however, more recently treated patients (era II) had more lymph node-positive primary tumors, shorter disease-free intervals, more extrahepatic disease, and smaller tumors. Median follow-up was 36 months for all patients and 63 months for survivors. Median and 5-year disease-specific survival (DSS) were better in era II (64 months and 51% versus 43 months and 37%, respectively; p < 0.001); but median and 5-year recurrence-free survival (RFS) for all patients were not different (23 months and 33% era II versus 22 months and 27% era I; p = 0.16). There was no difference in RFS or DSS for high-risk (Clinical Risk Score >2, n = 506) patients in either era. There was a marked improvement in both RFS and DSS for low risk (Clinical Risk Score < or =2, n = 1,094) patients. CONCLUSIONS Despite worse clinical and pathologic characteristics, survival but not recurrence rates after hepatic resection for colorectal metastases have improved over time and might be attributable to improvements in patient selection, operative management, and chemotherapy. The improvement in survival over time is largely accounted for by low-risk patients.