ABSTRACT
BACKGROUND/AIM: Immune checkpoint inhibitors (ICIs) have an important role in lung cancer therapy. Although the programmed cell death protein-1 (PD-L1) tumor proportion score (TPS) and tumor mutational burden are known prognostic factors, they are insufficient to predict clinical outcomes. This study was conducted to identify novel biomarkers for ICI treatment. PATIENTS AND METHODS: We performed univariable and multivariable analyses of 110 patients with advanced non-small-cell lung cancer (NSCLC) who were treated with an ICI to identify novel biomarkers related to prognosis. We assessed their backgrounds, such as performance status (PS), PD-L1 TPS, smoking status, and peripheral white blood cell counts at baseline and on the day the second course of ICI administration. RESULTS: In the multivariable analysis, PS, driver gene, immune-related adverse events, and post-treatment absolute neutrophil counts (post-ANCs) were significantly associated with progression-free survival. CONCLUSION: A high level of post-ANCs was associated with poor outcome in ICI-treated NSCLC patients.