Prognostic significance of pretreatment total lymphocyte count and neutrophil-to-lymphocyte ratio in extensive-stage small-cell lung cancer.

Abstract

We evaluated pretreatment total lymphocyte count (TLC, marker of immunosuppression), neutrophil-to-lymphocyte ratio (NLR, marker of inflammation), and overall survival (OS) in patients with extensive-stage small-cell lung cancer (ES-SCLC). Pretreatment blood characteristics, age, sex, performance status, race, stage (M1a vs. M1b), number and location of metastases, weight loss, smoking status, chemotherapy cycles (<4 vs. ≥4), thoracic radiotherapy dose (<45 vs. ≥45 Gy), and receipt of prophylactic cranial irradiation (PCI) were evaluated in 252 patients with ES-SCLC treated in 1998-2015. Factors significant in univariate analysis were selected as covariates for a multivariate Cox model. Pretreatment TLC was below normal (<1.0 × 10³/µL) in 58 patients (23%). Median OS time was 11.0 months and was worse for those with TLC ≤ 1.5 × 10³/µL (9.8 vs. 12.0 months) and pretreatment NLR > 4.0 (9.4 vs. 13.9 months). Multivariate analysis identified low TLC (hazard ratio [HR] 0.734, 95% confidence interval [CI] 0.565-0.955, P = 0.021) and high NLR (HR 1.521, 95% CI 1.172-1.976, P = 0.002) as predicting inferior survival. Age (>63 y), sex (male), performance status (≥2), chemotherapy cycles (<4), radiation dose (<45 Gy), and no PCI also predicted worse OS (P < 0.05). Pretreatment TLC and NLR may be useful for stratifying patients with ES-SCLC for treatment approaches.