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.