ESTRO 2025 - Abstract Book

S503

Clinical - Breast

ESTRO 2025

1943

Digital Poster Safety and cardiac assessment of 5-fraction whole breast irradiation after breast-conserving surgery: SAFE FORWARD trial (NCT04842409) Viola Salvestrini 1 , Carlotta Becherini 1 , Livia Marrazzo 2 , Giuseppe Barletta 3 , Luca Visani 1 , Marianna Valzano 1 , Isacco Desideri 1 , Giulio Francolini 1 , Niccolò Bertini 1 , Beatrice Bettazzi 1 , Cecilia Petruccioli 1 , Maria Riccarda Del Bene 3 , Giuseppe Pilato 3 , Stefania Pallotta 2 , Lorenzo Livi 1 , Icro Meattini 1 1 Radiation Oncology, Azienda Ospedaliero Universitaria Careggi, Università di Firenze, Florence, Italy. 2 Medical Physics Unit, Azienda Ospedaliero Universitaria Careggi, Università di Firenze, Florence, Italy. 3 Diagnostic Cardiology, CardioThoracic and Vascular Department, Azienda Ospedaliero Universitaria Careggi, Università di Firenze, Florence, Italy Purpose/Objective: Ultra-hypofractionated 5-fraction radiation therapy (RT) after breast-conserving surgery (BCS) reports non-inferior local control rates and good toxicity profile. This study evaluates left ventricular (LV) and right ventricular (RV) function using standard and three-dimensional (3D) echocardiography, as well as LV global longitudinal strain (LV GLS) and free-wall RV linear strain (FWRV-LS) in patients receiving 26Gy in 5 daily fractions as postoperative RT schedule for whole breast irradiation (WBI). Material/Methods: SAFE-FORWARD (NCT04842409) is an observational prospective study including invasive breast cancer patients receiving WBI (26Gy/5) after BCS. Patients were treated with tangential IMRT fields (6 or 10 MV beams). Patients had clinical-instrumental cardiac assessment before RT and at 2-, 6-, 12- and 24-month after treatment. Heart substructures were delineated following the cardiac contouring atlas. Both acute and late toxicity were evaluated according to CTCAE (v5) scales. Primary endpoints included 3D-LV ejection fraction (3D-LVEF) and 3D-RVEF, volumes, LV-GLS and FWRV-LS changes.