PurposeThe optimal stereotactic ablative body radiotherapy (SABR) delivery schedule in stage I non-small cell lung cancer (NSCLC) remains unclear. This population-based study investigated grade ≥ 2 toxicity rates, local failure (LF), and overall survival (OS) in patients treated with 48 Gy in 4 fractions scheduled every other day (QOD) versus daily with weekends (QDW) and consecutive daily without weekends (QD). Materials and MethodsBetween January 2019 and June 2022, treatment records using 48 Gy in 4 fractions were extracted from a provincial cancer registry and grouped by delivery as QOD, QDW, or QD. Toxicity events were recorded using CTCAE v5.0. The Kaplan-Meier method was used to compute OS while LF was calculated using cumulative incidence methods with death as a competing risk. Cox regression analyses and Fine-Gray modelling was used to assess for variables associated with OS and LF, respectively. ResultsOf 404 patients meeting study criteria, 190, 111, and 103 received QOD, QDW, and QD SABR, respectively. More patients receiving QDW SABR were medically inoperable and more patients receiving QD SABR had tumors abutting the chest wall. Median follow-up was 29.5 months (interquartile range [IQR] 19.2-38.4). Overall toxicity was low, with crude rates of acute and late grade ≥ 2 toxicity not being statistically different among the groups. No grade 4 or 5 toxicities were recorded. LF rates at 24 months were not different at 7.5% (95% confidence interval [CI] 3.7-11.3), 9.5% (95% CI 3.9-15.1), and 11.0% (95% CI 4.9-17.2) for the QOD, QDW, and QD groups, respectively (p = 0.60). QDW and QD schedules were not associated with LR. Similarly, no significant differences in median OS were found among the QOD, QDW, and QD groups at 47.5 months (95% CI 39.26-55,74), 52.7 (95% CI 34.7-70.7), and 49.0 months (95% CI 31.6-66.4), respectively. QDW and QD schedules were not associated with OS. ConclusionsThis population-based study demonstrated no statistically significant differences in grade ≥ 2 toxicity rates, LF, and OS for stage I NSCLC patients treated with lung SABR using 48 Gy in 4 fractions delivered QOD, QDW, and QD. Patient convenience and optimization of resources may be considered when choosing a lung SABR treatment delivery schedule.
Read full abstract