High neutrophil-to-lymphocyte ratios confer poor prognoses in patients with small cell lung cancer

Background: The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are easily obtained from routine blood tests. We investigated the associations of the NLR and PLR with the clinical parameters and prognoses of small cell lung cancer (SCLC) patients. Methods: Pre-treatment clinical and laboratory data from 139 patients with SCLC were retrospectively studied with univariate analyses. The NLR and PLR values were divided into two separate groups: high NLR (>4.55, n = 32) vs low NLR (<= 4.55, n = 107) and high PLR (>148, n = 63) vs low PLR (<= 148, n = 76). Kaplan-Meier survival analyses and Cox proportional hazard models were used to examine the effects of NLR and PLR on overall survival. Results: Chi-square analyses revealed significant associations of high NLR with tumour stage, hepatic metastasis, radiotherapy and chemotherapy and significant associations of high PLR with tumour stage, bone and hepatic metastases, exposure to cooking oil fumes, and chemotherapy. Mann-Whitney U tests demonstrated an association of high NLR with smoking exposure, and high NLR and high PLR were correlated with several laboratory parameters. Kaplan-Meier analyses revealed that high NLR and high PLR conferred poor prognoses for SCLC patients. Moreover, multivariate analysis demonstrated that NLR, tumour stage, and hepatic metastasis were independent prognostic factors for survival. In this study, we found that NLR and PLR were associated with several factors that reflect the inflammatory (white blood cell count, WBC; lactate dehydrogenase, LDH) and nutritional (albumin, ALB; haemoglobin, HB; and cholesterol) status of SCLC patients at diagnosis. Conclusions: NLR is an independent prognostic factor and can be used to predict the mortality risk of SCLC patients.