BACKGROUND: Approximately 15%-20% of all non-small cell lung cancer (NSCLC) cases present with stage I disease. Surgical resection traditionally offers the best chance of a cure but some patients will not have this treatment due to older age, comorbidities or personal choice. Stereotactic ablative radiotherapy (SABR) has become an established curative intent treatment option for patients who are not selected for or do not choose surgery. The aim of this study is to compare survival at 90 days, 6 months, 1 year and 2 years for patients who received either lobectomy or SABR. METHODS: We used data from the 2015 National Lung Cancer Audit database and linked with Hospital Episode Statistics and the radiotherapy dataset to identify patients with NSCLC stage IA-IB and performance status (PS) 0-2 who underwent surgery or SABR treatment. We assessed the likelihood of death at 90 days, 6 months, 1 year and 2 year after diagnosis and procedure date to observe survival between two patient groups. RESULTS: We identified 2373 patients in our cohort, 476 of whom had SABR. The median difference between date of diagnosis and date of treatment for surgery patients was 17 days while for SABR patients it was 73 days. Increasing age and worsening PS were associated with having SABR rather than surgery. Survival between the two treatment modalities was similar early on but by 1-year people who had surgery did better than those who had SABR (adjusted ORs 2.12, 95% CI 1.35 to 2.31). This difference persisted at 2 years and when the analysis was restricted to patients aged <80 years and with PS 0 or 1 and stage IA only. CONCLUSION: Our analysis suggests that patients who have lobectomy have a better survival compared with SABR patients; however, we found considerable delays in patients receiving SABR which may contribute to poorer long-term outcomes with this treatment option. Reducing these delays should be a key focus in development and reorganisation of services.