Prognostic Significance of Total Lymphocyte Count, Neutrophil-to-lymphocyte Ratio, and Platelet-to-lymphocyte Ratio in Limited-stage Small-cell Lung Cancer

Abstract

Background: We sought reliable markers of survival and disease control among patients treated for limited-stage small-cell lung cancer (LS-SCLC).

Patients and methods: Subjects were 122 patients given (chemo)radiotherapy for LS-SCLC at MD Anderson in 2002 through 2015. Pretreatment total lymphocyte count (TLC), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) were analyzed for associations with overall (OS) and progression-free survival. Optimal cutoff values were identified with receiver operating characteristic curves and survival probabilities with the Kaplan-Meier method.

Results: Pretreatment TLC was 1.86 × 10³/μL (±0.88); NLR, 3.44 (±3.69); and PLR, 170.53 (±101.56); corresponding cutoffs were 1.9, 2.9, and 140.1. Higher TLC was associated with superior median and 2-year OS (17.4 vs. 15.7 months and 33% vs. 29%; P = .029), and higher NLR and PLR with worse median and 2-year OS (NLR: 14.9 vs. 17.8 months, 29% vs. 31%; P = .026; PLR: 14.8 vs. 18.9 months, 24% vs. 37%; P = .009). Multivariate Cox regression adjusted for age, disease stage, number of chemotherapy cycles, and use of prophylactic cranial irradiation confirmed the links between high TLC and superior OS (hazard ratio [HR] 0.55; 95% confidence interval [CI], 0.32-0.94; P = .028) and between high NLR and PLR and inferior OS (NLR: HR, 1.86; 95% CI, 1.15-3.01; P = .011; PLR: HR, 1.72; 95% CI, 1.06-2.82; P = .030).

Conclusions: Baseline lymphopenia was an indicator of poor prognosis in patients with LS-SCLC.

Keywords: Chemoradiation; Lymphopenia; Neutrophil-to-lymphocyte ratio; Overall survival; Small cell lung cancer.