The management of stage I Non-Small cell lung cancer (NSCLC) in Ontario: A Population-Based study of patterns of care and Stereotactic Ablative Body radiotherapy (SABR) utilization from 2010 to 2019

•This population-based study describes the management of stage I NSCLC, 2010–2019.•The utilization of SABR increased, while surgery and observation decreased.•Substantial practice variation was observed amongst the 14 Ontario health regions.•From 2010 to 2019, 2 yr-OS and CSS over time improved for all stage I and surgically managed patients. Stereotactic Ablative Body Radiotherapy (SABR) is the standard of care for medically inoperable patients with Stage I NSCLC. The adoption of SABR and its association with cancer outcomes requires characterization. We described the management of biopsy-proven Stage I NSCLC with SABR, surgery, non-SABR curative radiotherapy (RT) and observation in Ontario, Canada, between 2010 and 2019. Temporal and geographic trends in practice and survival outcomes were analyzed. This was a retrospective population-based cohort study conducted by linking electronic radiotherapy (RT) records to a population-based cancer registry. A total of 12,065 patients were identified, 61.7 % underwent surgery, 17.9 % received SABR, 8.6 % received non-SABR curative RT and 11.7 % were observed. Between 2010 and 2019, the utilization of surgery decreased (63.8 % to 49.9 %, p