Neutrophil to lymphocyte ratio may predict efficacy of anti-PD-1 inhibitors in advanced EGFR-mutant non-small cell lung cancer: retrospective cohort study

Abstract This study aimed to investigate the associations between the clinical characteristics and effectiveness of anti-PD-1 inhibitors in patients with EGFR-sensitive mutations, aiming to identify the potential subgroup of patients who might benefit from anti-PD-1 inhibitor treatment. Patients with advanced non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR)-sensitive mutations who received subsequent anti-PD-1 inhibitors in combination with chemotherapy/antiangiogenic agents or alone after progression to tyrosine kinase inhibitors (TKIs) were screened. Clinical characteristics, including hematological parameters, were investigated for potential correlations with clinical outcomes. Subgroup and multivariate analyses were used for further confirmation of the relationship. Kaplan–Meier curves and Cox survival regression models using the log-rank test were used for progression-free survival (PFS) and overall survival (OS) assessments between the groups. Multiple regression analysis was performed using the standard regression coefficient values. The Wilcoxon test was used for the analysis of the variation in NLR . P ≤ 0.05 was considered to indicate statistical significance. This study was a retrospective study. Twenty-two patients met the inclusion criteria and were included in the study. The median PFS was 3.05 months (95% CI, 2.9–10.2 months). The median OS was 7.30 months (95% CI, 5.2–18.1 months). PFS in low neutrophil to lymphocyte ratio (NLR ≤ 4) was significantly longer than high NLR (NLR > 4, 5.7 months versus 2.0 months, HR, 0.35, 95% CI, 0.08–0.63, P = 0.0083). The OS in the low NLR group was also significantly better than that in the high NLR group (OS, 21.3 months versus 5.0 months, HR, 0.33; 95% CI, 0.09–0.74; P = 0.0163). In the multivariate analysis, NLR was the only significant factor for OS benefits (β = 3.535, 95% CI, 1.175–10.636, P = 0.025). Further investigation revealed that front-line TKIs exposure may contribute to the elevation or decrease of NLR, and finally lead to different efficacy outcomes by anti-PD-1 inhibitors. The findings suggest that a portion of advanced NSCLC patients with low NLR characteristics (NLR ≤ 4), even those harboring EGFR-sensitive mutations, could benefit from anti-PD-1 inhibitors as further line treatment after progression to EGFR-TKIs.