A Study to Determine the Feasibility and Acceptability of Conducting a Phase III Randomised Controlled Trial Comparing Stereotactic Ablative Radiotherapy With Surgery in paTients With Peripheral Stage I nOn-small Cell Lung Cancer cOnsidered Higher Risk of Complications From Surgical Resection

Stage I non-small cell lung cancer (NSCLC) is curable and surgery is considered the standard of care for fit, good performance status patients. However, a high proportion of patients with stage 1 NSCLC are elderly and/or have medical co-morbidities and are therefore at higher risk of surgical complications. The optimal treatment for these patients is unknown. SABR may be an equally appropriate treatment but this need to be formally assessed. Funded by the NIHR Research for Patient Benefit, SABRtooth is a UK multi-centre, two-group individually randomised controlled feasibility study of patients with peripheral stage I non-small cell lung cancer considered at higher risk from surgery. In total, 54 patients are planned to be recruited from 4 treatment sites and 2 referral sites. This study aims to determine the feasibility and acceptability of performing a largescale definitive randomised phase III trial comparing surgery with stereotactic ablative radiotherapy (SABR). The qualitative substudy is an exploration of the reasons for nonparticipation in the SABRTooth trial. As the two treatments are very different, patients may have a strong preference for either surgery or SABR, or may feel uncomfortable to have a decision between such distinct options taken out of their hands. Understanding why patients choose not to participate or do not take up their treatment allocation will be crucial in demonstrating that recruiting to a larger scale phase III trial is feasible. We will explore what patients, who have declined particpation in the study or who intiailly consented but subsequently fail to take up their randomimsed treatment arm, understand, perceive and feel about, how the SABRTooth trial was presented to them and their expectations of study burden.