ESTRO 2025 - Abstract Book

S605

Clinical - Breast

ESTRO 2025

4041

Proffered Paper Radiation therapy management in BRCA1/2 carriers diagnosed with early breast cancer Carlotta Becherini 1,2 , Eva Blondeaux 3 , Luca Visani 1,2 , Virginia Delucchi 3 , Luca Boni 3 , Matteo Lambertini 4,5 , Icro Meattini 2,1 , for the BRCA BCY Collaboration 6 1 Radiation Oncology, Azienda Ospedaliero Universitaria Careggi, Firenze, Italy. 2 Department of Experimental and Clinical Biomedical Sciences M. Serio, University of Florence, Firenze, Italy. 3 U. O. Epidemiologia Clinica, IRCCS Ospedale Policlinico San Martino, Genova, Italy. 4 Department of Internal Medicine and Medical Specialties (DIMI), School of Medicine, University of Genova, Genova, Italy. 5 Department of Medical Oncology, U. O. Clinica di Oncologia Medica, IRCCS Ospedale Policlinico San Martino, Genova, Italy. 6 BRCA BCY Collaboration, BRCA BCY Collaboration, Bruxelles, Belgium Purpose/Objective: Current guidelines recommend bilateral mastectomy for BRCA mutation carriers, yet comparative evidence on survival and recurrence outcomes remains limited [1,2]. This study evaluates outcomes in the largest published cohort of young BRCA1/2 mutation carriers with breast cancer (BC) treated with breast-conserving surgery (BCS) plus radiation therapy (RT) or mastectomy (with or without RT) for the primary tumour [3] Material/Methods: We analysed 4,837 BRCA1/2-carriers diagnosed with invasive BC at age ≤40 years between 2000 and 2020. Treatments for the primary tumour included BCS+RT (n=1,704), mastectomy alone (n=1,488), or mastectomy with RT (n=1,645). The primary endpoints were locoregional or contralateral (LorC) BC and overall survival (OS). Results: Patients were well-balanced for baseline characteristics, although advanced disease was more common in the mastectomy+RT group ( Table 1 ).