LAUSR

INTRODUCTION There is unmet need to explore the predictive biomarkers of PD-1/PD-L1 inhibitors in patients with non-small-cell lung cancer (NSCLC). Here, we aimed to investigate the predictive and prognostic value of blood neutrophil-to-lymphocyte ratio (NLR) in NSCLC patients treated with PD-1/PD-L1 inhibitors. METHODS We performed a comprehensive online search to explore the association between blood NLR and overall survival (OS) or progression-free survival (PFS) in NSCLC patients received PD-1/PD-L1 inhibitors. Published data including hazard ratios (HRs) and 95% confidence interval (CI) were eligible. Pooled estimates of treatment outcomes were calculated using Stata/MP 14.1. RESULTS 1700 patients from sixteen studies were included. The pooled results suggested that high blood NLR was correlated with significantly shorter OS (HR = 2.07, P < 0.001) and PFS (HR = 1.59, P < 0.001). The predictive and prognostic significance of blood NLR were observed consistently across most subgroups including publication year, study design, research region, PD-L1 expression detection, sample size, NLR cutoff, median follow-up time and study quality score. Additionally, there was a significant correlation between elevated NLR cutoff values and OS benefit (r = 0.585, P =  0.036) but not for PFS benefit (r = 0.198, P =  0.496). Notably, HRs of PFS showed significant correlation with HRs of OS (r = 0.686, P =  0.041). CONCLUSION Elevated blood NLR was associated with shorter PFS and OS in NSCLC patients treated with PD-1/PD-L1 inhibitors, suggesting its potential predictive and prognostic value in this clinical scenario.