Preoperative peripheral blood lymphocyte-to-monocyte ratio is a prognostic indicator in oral squamous cell carcinoma: a retrospective study in a single institution

Although lymphocyte-to-monocyte ratio (LMR) has been shown to be a prognostic indicator in various cancers, the prognostic value of preoperative LMR in patients with oral squamous cell carcinoma has not been reported. The aim of this study was to evaluate whether preoperative LMR could predict the outcomes of patients with oral squamous cell carcinoma. We studied 210 patients who underwent curative surgery for oral squamous cell carcinoma in Tokyo Dental College, Chiba Hospital between January 2007 and December 2011. LMR was calculated from the preoperative peripheral blood cell counts. The optimal cutoff point of LMR was determined on the basis of a time-dependent receiver operating characteristics curve for overall survival. A total of 94 patients met the inclusion criteria. The low LMR group had a significantly lower survival rate than the high LMR group (p= 9.44 × 10-11, log-rank test). Univariate analysis using a Cox proportional-hazards model showed that N classification, disease stage, and pretreatment LMR were significantly associated with poor outcomes. Multivariate analysis showed that pretreatment LMR (hazard ratio ［HR］: 0.07; 95% confidence interval ［CI］: 0.01-0.37, p= 2.12×10-3) remained as a risk factor for cancerrelated death. Thus, pretreatment LMR might be an independent prognostic biomarker in patients with oral squamous cell carcinoma.