Association between pretreatment neutrophil-to-lymphocyte ratio and immune-related adverse events due to immune checkpoint inhibitors in patients with non-small cell lung cancer

Background Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of advanced or recurrent non-small cell lung cancer (NSCLC). They cause immune-related adverse events (irAEs), but the underlying mechanisms and predictors remain to be fully elucidated. In this retrospective study, we investigated the association between pretreatment neutrophil-to-lymphocyte ratio (NLR) and the occurrence of irAEs. Methods The study involved 115 patients with NSCLC who started ICI-only treatment in our hospital between January 2016 and April 2020. Results Forty-five patients (39.1%) had irAEs, and pretreatment NLR was significantly lower in the irAEs group than in the non-irAEs group (2.8 vs. 4.1; p = 0.036). The cutoff value of the NLR was 2.86 (area under curve, 0.62; sensitivity, 0.56; specificity, 0.71), and the incidence rate of irAEs was significantly higher in the NLR < 2.86 group than in the NLR >= 2.86 group (p = 0.004; odds ratio [OR]: 3.12; 95% confidence interval [CI]: 1.43-6.84). The multivariate analysis showed that the NLR was significantly associated with the occurrence of irAEs (p = 0.016; OR: 2.69; 95% CI: 1.21-6.01). Conclusions Low pretreatment NLR may be a predictive factor for the occurrence of irAEs. By focusing on the potential risk of irAEs in patients with a low pretreatment NLR, irAEs can be appropriately managed from an early period.