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

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.

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.

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 (p=0.044). Kaplan-Meier analysis showed that elevated WBC counts were significantly associated with shorter PFS (p<0.001). In multivariate Cox analysis, an elevated WBC count remained independently associated with poorer PFS [hazard ratio (HR)=4.625, 95% confidence interval (CI)=1.969-10.864, p<0.001]. An optimal CRP cutoff value of 0.555 mg/dL was identified via receiver operating characteristic analysis. Elevated CRP levels were independently associated with worse OS (HR=2.251, 95%CI=1.110-4.567, p=0.025) and PFS (HR=1.729, 95%CI=1.080-2.769, p=0.023).

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.