Prognostic significance of combined preoperative platelet-to-lymphocyte ratio and lymphocyte-to-monocyte ratio in patients undergoing surgery with stage IB non-small-cell lung cancer

BACKGROUND: Research indicates that the presence of a systemic inflammatory response plays an important role in predicting survival in patients with cancer. The aim of this study was to investigate the prognostic value of preoperative neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio (PLR), prognostic nutritional index, and the combination of preoperative LMR and PLR (LMR-PLR) in predicting the survival of patients with stage IB non-small-cell lung cancer (NSCLC). MATERIALS AND METHODS: We retrospectively analyzed clinical data of 577 patients with stage IB NSCLC who underwent pneumonectomy from January 1999 to December 2009. Univariate and multivariate Cox survival analyses were used to evaluate the prognostic indicators, including LMR-PLR. The cutoff values for LMR and PLR were defined by the receiver operating characteristic (ROC) curve analysis. According to the ROC curve, the recommended cutoff values of LMR and PLR were 3.16 and 81.07, respectively. We divided the patients into three groups according to their LMR and PLR status and defined them with different scores. Patients with both high LMR (>3.16) and low PLR (≤81.07) were given a score of 2, whereas those with one or neither were scored 1 or 0, respectively. Survival curves were plotted using the Kaplan–Meier method and compared with the log-rank test. Cox proportional hazards analyses were used to identify the factors associated with overall survival (OS). RESULTS: The median follow-up time was 93.77 months. The allocation of the LMR-PLR score was as follows: LMR-PLR = 0, 193 (33.4%) patients; LMR-PLR = 1, 308 (53.4%) patients; and LMR-PLR = 2, 76 (13.2%) patients. After multivariate analysis, our results showed that LMR-PLR was an independent prognostic indicator for OS (P=0.001). The 10-year OS rates were 70.0%, 60.4%, and 49.5% for LMR-PLR =2, LMR-PLR =1, and LMR-PLR =0, respectively (P<0.001). CONCLUSION: This study demonstrated that preoperative LMR and PLR are simple, readily available, and low-cost biomarkers. Preoperative LMR-PLR score can be used as a valuable prognostic marker for long-term survival in stage IB NSCLC patients who underwent surgery.