ESTRO 2025 - Abstract Book

S4383

RTT - Treatment planning, OAR and target definitions

ESTRO 2025

3667

Digital Poster dosimetric evaluation to the cardiac substructures in a cohort of patients with breast cancer treated with fast forward schedule radiotherapy Daniela P Doino 1 , Federica Piccolo 1 , Carla Bianchi 2 , Paola Stucchi 2 , Stefania Gottardo 1 , Marianna Montesano 1 , Redona Tafili 1 , Raffaela Abate 3,1 , Francesca A. Rovera 4 , Marinella Molteni 1 , Fabio Tanzi 2 , Italo Dell'Oca 1 1 Radiotherapy, ASST dei Sette Laghi-Ospedale di Circolo e Fondazione Macchi, Varese, Italy. 2 MedicalPhysics, ASST dei Sette Laghi-Ospedale di Circolo e Fondazione Macchi, Varese, Italy. 3 Radiotherapy, University of Milan, Milano, Italy. 4 medicine and technological innovation, University of Insubria, Varese, Italy Purpose/Objective: The aim of this preliminary analysis is to evaluate the dose to the whole heart and to the cardiac substructures as left ventricle (LV), right ventricle (RV), left atrium (LA), right atrium (RA), left anterior descending (LAD) in a single institutional cohort of 17 consecutive patients (pts) diagnosed with localized breast cancer treated with adjuvant radiotherapy with an ultra-hypofractionated Fast Forward schedule. Material/Methods: Between December 2021 and May 2023, 17 consecutive pts, median age 79 yrs, Inter Quartile Range (IQR) 76-84 yrs, received adjuvant ultra-hypofractioned whole breast radiotherapy after primary surgery for early breast cancer with the Fast Forward schedule 26 Gy in 5 fr at 5,2 Gy/fr +/- tumor bed boost of 10 Gy in 5 fr at 2 Gy/fr. Patient characteristics are reported in Table 1. All pts were treated with 3D-CRT with free breathing technique and beam energy 6 MV Photon. Retrospectively the cardiac substructures LV, RV, LA, RA, LAD were contoured and whole heart was re-contoured by a single radiation oncologist. For each treatment the dosimetry was recalculated using cardiac dose constraints adjusted for ultra hypofractionated regime (1).