Prognostic Significance of the Lymph Node Ratio in Stage IV Colorectal Cancer Patients who have Undergone Curative Resection

The lymph node ratio (LNR) was proposed as a prognostic indicator in Stage III colorectal cancer (CRC) patients in recent studies. The purpose of this study was to evaluate the prognostic impact of the LNR in Stage IV CRC patients who have undergone curative resection. A retrospective review of 119 Stage IV CRC patients who underwent curative resection in our institute from 1997 to 2009 was performed. Patients were divided into two groups (low LNR and high LNR) by means of their median LNR. A disease-free survival (DFS) and an overall survival (OS) were analyzed using the Kaplan-Meier curve; multivariate analysis was performed using the Cox proportional hazard model. The cutoff value for the LNR was 0.111. For the entire study group, the 5-year DFS was 22 % and the 5-year OS was 65 %. DFS was not significantly different between patients in the low LNR group and the high LNR group (25 and 19 %, respectively; P = 0.317), but OS was significantly higher in the low LNR group patients compared with the high LNR group patients (77 and 54 %, respectively; P < 0.001). Using multivariate analysis, we identified the LNR as an independent prognostic factor for OS, with a hazard ratio of 3.08 (95 % CI 1.38-8.19; P = 0.005). LNR is a potent prognostic indicator for stratification in Stage IV CRC patients who have undergone curative resection.