The impact of neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio among patients with intrahepatic cholangiocarcinoma

Background Neutrophil-to-lymphocyte ratio and platelets-to-lymphocyte ratio may be host factors associated with prognosis. We sought to determine whether neutrophil-to-lymphocyte and platelets-to-lymphocyte ratio were associated with overall survival among patients undergoing surgery for intrahepatic cholangiocarcinoma. Methods Patients who underwent resection for intrahepatic cholangiocarcinoma between 1990 and 2015 were identified from 12 major centers. Clinicopathologic factors and overall survival were compared among patients stratified by neutrophil-to-lymphocyte ratio and platelets-to-lymphocyte ratio. Risk factors identified on multivariable analysis were included in a prognostic model and the discrimination was assessed using Harrell's concordance index (C index). Results A total of 991 patients were identified. Median neutrophil-to-lymphocyte ratio and platelets-to-lymphocyte ratio were 2.7 (interquartile range [IQR]: 2.0–4.0) and 109.6 (IQR: 72.4–158.8), respectively. Preoperative neutrophil-to-lymphocyte ratio was elevated (≥5) in 100 patients (10.0%) and preoperative platelets-to-lymphocyte ratio (≥190) in 94 patients (15.2%). Patients with low and high neutrophil-to-lymphocyte ratio and platelets-to-lymphocyte ratio generally had similar baseline characteristics with regard to tumor characteristics. Overall survival was 37.7 months (95% confidence interval [CI]: 32.7–42.6); 1-, 3-, and 5-year overall survival was 78.8%, 51.6%, and 39.3%, respectively. Patients with an neutrophil-to-lymphocyte ratio <5 had a median survival of 47.1 months (95% CI: 37.9–53.3) compared with a median survival of 21.9 months (95% CI: 4.8–39.1) among patients with an neutrophil-to-lymphocyte ratio ≥5 (P = .001). In contrast, patients who had a platelets-to-lymphocyte ratio <190 vs platelets-to-lymphocyte ratio ≥190 had comparable long-term survival (P > .05). On multivariable analysis, an elevated neutrophil-to-lymphocyte ratio was independently associated with decreased overall survival (hazard ratio: 1.04, 95% CI: 1.01–1.07; P = .002). Patients could be stratified into low- versus high-risk groups based on standard tumor-specific factors such as lymph node status, tumor size, number, and vascular invasion (C index 0.62). When neutrophil-to-lymphocyte ratio was added to the prognostic model, the discriminatory ability of the model improved (C index 0.71). Conclusion Elevated neutrophil-to-lymphocyte ratio was independently associated with worse overall survival and improved the prognostic estimation of long-term survival among patients with intrahepatic cholangiocarcinoma undergoing resection.