Pretreatment Immune Parameters Predict for Overall Survival and Toxicity in Early-Stage Non–Small-Cell Lung Cancer Patients Treated With Stereotactic Body Radiation Therapy

Abstract

IntroductionWe determined whether pretreatment immunologic parameters could predict the outcomes and toxicity in early-stage non–small-cell lung cancer (NSCLC) patients treated with stereotactic body radiation therapy (SBRT). Patients and MethodsThe pretreatment leukocyte, lymphocyte, and neutrophil counts, serum albumin levels, neutrophil-to-lymphocyte ratio (NLR,) and platelet-to-lymphocyte ratio (PLR) were evaluated to determine the association with locoregional control, distant metastasis-free survival (DMFS), disease-specific survival (DSS), overall survival (OS), and treatment-related toxicity. The survival rates were estimated with Kaplan-Meier analysis and multivariate analysis using the Cox proportional hazards model. ResultsThe data from 118 patients with a median follow-up period of 28.9 months were assessed. The 3-year local control, regional control, and DMFS rates were 97%, 87%, and 92%, respectively. The 3-year OS and DSS rates were 77% and 85%, respectively. On univariate analysis, none of the pretreatment immune parameters predicted for disease control. A higher NLR (P = .008), PLR (P = .002), neutrophil count (P = .059), and the presence of lymphocytopenia (P = .032) independently prognosticated for poor OS. Receiver operating characteristic curve analysis found NLRs > 2.18 and PLRs > 187.27 optimally predicted for poor 3-year OS (P = .0262 and P = .0089, respectively). A higher NLR predicted against the development of any symptomatic toxicity and against the development of symptomatic (grade ≥ 2) radiation pneumonitis on univariate analysis, and a higher serum albumin level independently predicted for the development of symptomatic radiation pneumonitis (P = .0491). ConclusionIn the setting of SBRT, an elevated pretreatment NLR, PLR, and neutrophil count and the presence of lymphocytopenia independently predicted for poor OS. Patients who presented with higher NLRs and lower serum albumin levels experienced less treatment-related symptomatic toxicity.