Discontinuous stereotactic body radiotherapy schedule increases overall survival in early-stage non-small cell lung cancer.

ABSTRACT

OBJECTIVES: The duration of stereotactic body radiotherapy (SBRT) for early-stage non-small cell lung cancer (NSCLC) may affect patient outcomes. We aimed to determine the impact of a continuous versus discontinuous SBRT schedule on local control (LC) and overall survival (OS) in NSCLC patients. MATERIALS AND METHODS: Consecutive NSCLC stage I patients (475) treated with SBRT in four centers were retrospectively analyzed. The delivered dose ranged from 48 to 75 Gy in 3-10 fractions. Based on the ratio between the treatment duration (TD) and number of fractions (n), patients were divided into two groups continuous schedule (CS) (TD ≤ 1.6n; 239 patients) and discontinuous schedule (DS) (TD > 1.6n; 236 patients). LC and OS were compared using Cox regression analyses after propensity score matching (216 pairs). RESULTS: The median follow-up period was 41 months. Multivariate analysis showed that the DS (hazard ratio (HR) 0.42; 95 % confidence interval (CI) 0.22-0.78) and number of fractions (HR 1.24; 95 % CI 1.07-1.43) were significantly associated with LC. The DS (HR 0.67; 95 % CI 0.51-0.89), age (HR 1.02; 95 % CI 1-1.03), WHO performance status (HR 2.27; 95 % CI 1.39-3.7), and T stage (HR 1.4; 95 % CI 1.03-1.87) were significantly associated with OS. The 3-year LC and OS were 92 % and 64 % and 81 % and 53 % for DS and CS treatments, respectively (p < 0.01). Cox analysis confirmed that the discontinuous SBRT schedule significantly increased LC and OS. CONCLUSION: DS is associated with significantly improved LC and OS in early-stage NSCLC patients treated with SBRT.