BEAT-BREAST: IMPROVING OUTCOMES FOR BREAST CANCER PATIENTS WITH BRAIN METASTASES A NON-RANDOMISED MULTI-CENTRE PHASE 2 FEASIBILITY TRIAL IN PATIENTS WITH PRIMARY BREAST CANCER WITH BRAIN METASTASES WHO ARE NOT SUITABLE FOR STEREOTACTIC RADIOTHERAPY

Abstract AIMS To evaluate the feasibility of delivering Dose Escalated Internal PTV Volumetric Arc Therapy (DE-iPTV VMAT) and assess its impact on health-related quality of life (HRQoL) in adult patients (16+) with brain metastases from breast cancer who are not suitable for other treatment options. METHODS Single-arm, non-randomized Phase 2 pilot trial in 62 patients over a 22-month period. Eligible patients will receive DE-iPTV VMAT, a novel radiotherapy technique designed to deliver higher doses to the tumour while minimizing radiation exposure to healthy brain tissue. Primary objective: assess the feasibility of delivering DE-iPTV VMAT and collecting HRQoL data. Secondary endpoints: overall survival, steroid usage, tumour response, and cost-effectiveness. We have incorporated patient and caregiver representatives as collaborators to ensure the study aligns with their needs and priorities. Their contributions include reviewing trial documents, providing feedback on the study design, and helping to outline planned focus groups. RESULTS Awaiting approval by REC/ HRA – aiming to open at first site March 2025. Key findings will include: feasibility of delivering DE-iPTV VMAT, observed effects on HRQoL; changes in sur- vival, steroid usage, or tumour response. We have actively engaged patients, caregivers, and clinicians throughout the development of this trial. Their valuable insights and feedback have been crucial in shaping the study design. Early PPIE work highlighted the need to shift our original trial design from a randomized to a non-randomized feasibility trial. The first focus group will address key questions and generate further topics for subsequent discussions. CONCLUSION This pilot study will provide valuable data on the feasibility and potential clinical benefits of DE-iPTV VMAT for patients with brain metastases from breast cancer. Findings from this trial will inform the design of a larger, definitive trial to further investigate the efficacy and safety of this novel radiotherapy approach.