Association Between Pretreatment White Blood Cell Count and Early Progression in Non-small Cell Lung Cancer.

Background/Aim: Elevated white blood cell (WBC) counts, frequently observed in patients with non-small cell lung cancer (NSCLC), are associated with poor prognosis; however, their relevance in the era of immune checkpoint inhibitor (ICI)-based therapy remains unclear. Patients and Methods: We retrospectively analyzed 103 patients with advanced or recurrent NSCLC. Patients were stratified according to the presence of leukocytosis (WBC ≥10,000/μl). Clinical characteristics, treatment responses, progression-free survival (PFS), and overall survival (OS) were compared between groups. Multivariate Cox proportional hazards models were used to identify independent prognostic factors. Results: Patients with elevated WBC counts were younger, had higher C-reactive protein (CRP) levels, tended to have a higher frequency of PD-L1 tumor proportion score (TPS) positivity at baseline, and exhibited a significantly lower objective response rate to first-line therapy ( Conclusion: Pretreatment leukocytosis was associated with early disease progression in NSCLC, even in PD-L1-positive cases. Furthermore, elevated CRP levels provided additional prognostic stratification for PFS and OS. Thus, WBC count and CRP may serve as practical and readily accessible tools for early treatment evaluation and risk stratification in the management of NSCLC in the ICI era.