Population-based analysis of single-fraction versus multi-fraction stereotactic ablative radiotherapy for early-stage non-small cell lung cancer.

Abstract

ObjectivesOptimal dose fractionation of stereotactic ablative radiotherapy (SABR) in early-stage non-small cell lung cancer (NSCLC) remains unclear. This population-based study compares outcomes and toxicities of single-fraction (SF) versus multi-fraction (MF) SABR.MethodsAll patients in British Columbia, Canada with peripheral T1-2N0 NSCLC treated with either SF-SABR (30 Gy or 34 Gy) or MF-SABR (48 Gy/4 or 54 Gy/3 fractions) between January 2021 and August 2024 were retrospectively reviewed. Local failure (LF) and overall survival (OS) were estimated using Kaplan-Meier method and cumulative incidence functions with death as a competing risk. Toxicity was graded per Common Terminology Criteria for Adverse Events version 5.0. Fine-Gray and Cox regression analyses were used to identify variables associated with LF and OS, respectively. Binary logistic regression was used to assess predictors of chest wall toxicity (CWT).ResultsA total of 814 lesions in 778 patients were included (SF-SABR 283 and MF-SABR 531). Median follow-up was 25.8 months (interquartile range, 18.8-36.6). No significant differences were observed in 2-year LF (3.5% vs. 4.8%, p = 0.11) or 2-year OS (79.3% vs. 79.4%, p = 0.62). There were no differences in any grade 2 toxicity (11.5% vs. 12.4%, p = 0.13), any grade 3-5 toxicity (1.5% vs. 3.9%, p = 0.08), or grade 2 + CWT (5.0% vs. 5.0%, p = 0.98). SF-SABR alone did not predict worse LF, OS, any grade 2 + toxicity, or grade 2 + CWT.ConclusionNo statistically significant differences were observed in LF, OS, or toxicity between SF-SABR versus MF-SABR. SF-SABR should be considered for this patient population as it is convenient and cost-effective.