ESTRO 2025 - Abstract Book

S1551

Clinical – Mixed sites & palliation

ESTRO 2025

Conclusion: The study was closed prematurely due to poor accrual and futility. Preliminary results confirm feasibility of STAR, however suggest that patients with the recurrence of SHD-related VT after several RFCA procedures still benefit more from repeated RFCA compared to STAR.

Keywords: ventricular tachycardia

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Mini-Oral Real-world reirradiation treatment and disease characteristics: interim analysis of the prospective observational E2-RADIatE ReCare cohort Jonas Willmann 1,2 , Vincent Dick 3 , Marta Scorsetti 4 , Matthias Guckenberger 2 , Staša Jelerčič 5 , Barbara A. Jereczek Fossa 6,7 , Melanie Machiels 8 , Filippo Alongi 9 , Stefanie Corradini 10 , Corinne Faivre-Finn 11 , Igor Sirak 12 , Yolande Lievens 13 , Frances Duane 14 , Hossein Hemmatazad 15 , Orit Kaidar-Person 16 , Felix Oppong 17 , Coreen Corning 17 , Enrico Clementel 17 , Nathalie Elaut 17 , Joachim Widder 3 , Nicolaus Andratschke 2 1 Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, USA. 2 Department of Radiation Oncology, University Hospital Zurich, University of Zurich, Zurich, Switzerland. 3 Department of Radiation Oncology, Comprehensive Cancer Center Vienna, Medical University of Vienna, Vienna, Austria. 4 Department of Radiotherapy and Radiosurgery, , IRCCS Humanitas Research Hospital, Milan, Italy. 5 Department of Radiotherapy, Institute of Oncology Ljubljana, Ljubljana, Slovenia. 6 Dept. of Oncology and Hemato-oncology, University of Milan, Milan, Italy. 7 Dept. of Radiation Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy. 8 Department of Radiation Oncology, Iridium Netwerk, University of Antwerp, Health & Sciences, Antwerp, Belgium. 9 Department of Advanced Radiation Oncology, IRCCS Sacro Cuore Don Calabria, Negrar-Verona, Italy. 10 Department of Radiation Oncology, LMU University Hospital, Munich, Germany. 11 The Christie NHS Foundation Trust, University of Manchester, Manchester, United Kingdom. 12 Department of Oncology and Radiotherapy, University Hospital Hradec Králové, Hradec Králové, Czech Republic. 13 Department of Radiation Oncology, Ghent University Hospital and Ghent University, Ghent, Belgium. 14 St Luke's Radiation Oncology Network, Cancer Trials Ireland, Dublin, Ireland. 15 Department of Radiation Oncology, Inselspital, University Hospital Bern, University of Bern, Bern, Switzerland. 16 Department of Radiation Oncology, Sheba Medical Center, Ramat Gan, Israel. 17 N/A, EORTC Headquarters, Brussels, Belgium Purpose/Objective: Reirradiation is increasingly utilised in cancer care but there is a lack of high-level evidence and standards to guide clinical decision making. The ReCare cohort study is an ongoing pragmatic prospective observational study within the E 2 -RADIatE study (EORTC-ESTRO RADiotherapy InfrAstrucTure for Europe). This initial analysis explores the completeness of data collected and aims to describe the patterns of care, including the most common indications and treatment approaches in routine clinical practice. Material/Methods: The ReCare cohort study is enrolling patients treated with high-dose reirradiation to the thorax (including breast and chest wall), abdomen and pelvis in 14 hospitals in 10 European and Asian countries. Patients received either type 1 re-irradiation (geometrical overlap with the previously irradiated volume) or type 2 reirradiation (without overlap but concerns of toxicity) for various primary tumours, with a prescription dose of ≥50 Gy EQD2 or lower if cumulative dose are concerning for toxicity. There are no restrictions regarding radiotherapy techniques, surgery or concomitant or systemic therapies. Results: Between May 2023 and October 2024, 243 patients were included reirradiated for 280 lesions – including locoregional recurrences, metastases and second primary tumours. Median age was 71 years, 41.6% female, ECOG