Abstract
BACKGROUND: Prognostic biomarkers provide essential information about a patient's overall outcome. However, existing biomarkers are limited in terms of either sample collection, such as requiring tissue specimens, or the process, such as prolonged time for analysis. In view of the need for convenient and non-invasive prognostic biomarkers for oral cancer, we aimed to investigate the prognostic values of neutrophil-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, and platelet-to-lymphocyte ratio in patient survival. We also aimed to explore the associations of these ratios with the clinicopathologic characteristics of Japanese oral squamous cell carcinoma patients. METHODS: This study was a non-randomized retrospective cohort study in a tertiary referral center. We included 433 patients (246 men, 187 women) who underwent radical surgery for oral cancers between January 2001 and December 2013. We evaluated various risk factors for poor prognosis including neutrophil-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, and platelet-to-lymphocyte ratio with univariate and multivariate analyses. The disease-specific survival and overall survival rates of patients were compared among the factors and biomarkers. RESULTS: In multivariable Cox proportional hazards analysis, high neutrophil-to-lymphocyte ratio (hazard ratio 2.87, 95% confidence interval 1.59-5.19, P < 0.001), moderately or poorly differentiated histology (hazard ratio 2.37, 95% confidence interval 1.32-4.25, P < 0.001), and extranodal extension (hazard ratio 1.95, 95% confidence interval 1.13-3.35, P = 0.016) were independent predictors of disease-specific survival. High neutrophil-to-lymphocyte ratio (hazard ratio 2.30, 95% confidence interval 1.42-3.72, P < 0.001), moderately or poorly differentiated (hazard ratio 1.72, 95% confidence interval 1.07-2.76, P = 0.025), and extranodal extension (hazard ratio 1.79, 95% confidence interval 1.13-2.84, P = 0.013) were independent predictors of overall survival. CONCLUSIONS: Neutrophil-to-lymphocyte ratio might be a potential independent prognostic factor in Japanese oral squamous cell carcinoma patients.