ESTRO 2025 - Abstract Book

S1550

Clinical – Mixed sites & palliation

ESTRO 2025

3195

Poster Discussion STAR-VT randomised trial of cardiac radiosurgery for recurrent ventricular tachycardia in structural heart disease Jakub Cvek 1 , Lukas Knybel 1 , Jana Haskova 2 , Dan Wichterle 2 , Petr Peichl 2 , Radek Neuwirth 3 , Otakar Jiravsky 3 , Josef Kautzner 2 1 Department of Oncology, University Hospital Ostrava and Faculty of Medicine, Ostrava, Czech Republic. 2 Department of Cardiology, Institute for Clinical and Experimental Medicine (IKEM), Prague, Czech Republic. 3 Department of Cardiology, Podlesí Hospital Třinec, Třinec, Czech Republic Purpose/Objective: The study compares outcomes of stereotactic arrhythmia radiotherapy (STAR) and repeated radiofrequency catheter ablation (RFCA) for drug-refractory ventricular tachycardia (VT) in patients with structural heart disease (SHD) who failed after at least one RFCA in the expert centre (STAR VT trial; NCT04612140). Material/Methods: Between June 2020 and January 2024, patients were recruited in 2 centres and randomized to STAR or repeated RFCA in a 1:1 fashion by the covariate-adaptive algorithm. During the STAR (CyberKnife, Accuray), a dose of 25 Gy was delivered to cover at least 95 % of the planned target volume which was delineated by a co-registration of electroanatomical map of the arrhythmogenic substrate (CARTO 3, Biosense Webster) with the planning computed tomography scan. Repeated RFCA was performed according to corresponding guidelines and included epicardial ablation if applicable. Recurrence of sustained VT was the primary study endpoint. Results: A total of 22 patients (77 % males, aged 67±11 years, 27 % ischemic cardiomyopathy, LVEF 29±6 %, 3.1±1.3 previous RFCA) were enrolled (11 in each arm) and followed for 18±12 months. Median dose was 25 Gy (IQR 20-25) at the 79 % isodose (IQR 76-81). Homogeneity, conformality and coverage index was 1,24 (IQR 1,17-1,25), 1,27 (IQR 1,23-1,32), and 95,9 % (IQR 96,6-96,9), respectively. Patients after STAR compared to RFCA had non-significantly (P = 0.12) higher risk of VT recurrence and significantly (P <0.01) higher risk of repeated ablation for VT (Figure 1). There were 8 and only 2 crossovers from the STAR and RFCA arm, respectively. In addition, patients after STAR vs. RFCA required non-significantly (P = 0.20) more repeated ablation procedures (1.1±1.3 vs. 0.7±1.3, respectively).