Who can benefit from a liver surgery for metastatic colorectal cancer in the era of modern chemotherapy? A post hoc analysis of the MIROX phase III trial.

Abstract

3547 Background: Despite improvement in colorectal liver metastasis (CLM) treatment, survival after liver surgery remains highly variable. Several clinicopathologic prognostic factors have been reported whose validity in the era of modern chemotherapy remains to be defined. This study aimed to analyze the prognostic factors associated with survival after CLM resection. Methods: Clinicopathologic data of patients included in the MIROX phase III trial who underwent surgery for isolated CLMs were analyzed. The primary endpoints were 5-year overall survival (OS) and disease-free survival (DFS). Univariate Cox analysis was performed to identify associations with OS and DFS and select variables included in a multivariate model to determine their independent prognostic value. Results: A total of 181 patients were analyzed. The median follow-up period was 6.42 years (95% CI: 5.15-8.71), and the 5-year OS and DFS rates were 67.1% and 35.4%, respectively. On multivariate analysis, Fong's clinical risk score (CRS) as a categorical variable (CRS 0-1 vs 2-3 vs 4-5, p = 0.036) and polymorphonuclear neutrophil (PMN) count (>6000/mm3vs ≤6000/mm3, p = 0.006) before chemotherapy were found to be independent prognostic factors for OS. However, only Fong's CRS remained significantly associated with DFS (p = 0.027). The final OS model was used to establish a nomogram that allows individual OS estimations at 1, 3, 5, and 10 years. Conclusions: Fong's CRS and PMN count were independently associated with poor OS after CLM resection. Fong's CRS was also associated with DFS. The established prognostic nomogram could predict OS more accurately before CLM treatment.