ESTRO 2025 - Abstract Book

S541

Clinical - Breast

ESTRO 2025

long-term cardiac mortality (4% of patients) and one reported the incidence of second malignancy (3% of patients). None of the included studies assessed patient-reported outcomes using validated quality-of-life questionnaires. Conclusion: Repeat BCT using EBRT is an emerging alternative to salvage mastectomy, offering favourable local control and acceptable rates of treatment-related toxicities. Prospective studies incorporating patient-reported outcomes are needed to compare its effectiveness and safety to repeat BCT using other RT modalities and to salvage mastectomy.

Keywords: breast cancer, recurrence, re-irradiation

2774

Digital Poster Exclusive moderate hypofractionation in inoperable locally advanced breast cancer: a mono-istitutional experience. Sara Falivene 1 , Piera Ferraioli 1 , Valentina d'Alesio 1 , Francesca Buonanno 1 , Emanuela Esposito 2 , Esmeralda Scipilliti 1 , Vincenzo Ravo 1 , Paolo Muto 1 1 UOC Radioterapia, istituto Nazionale Tumori IRCCS Fondazione Pascale, Napoli, Italy. 2 UOC Chirurgia Senologica, istituto Nazionale Tumori IRCCS Fondazione Pascale, Napoli, Italy Purpose/Objective: Breast cancer surgery is the primary treatment for breast cancer. The effectiveness of neoadjuvant therapy has expanded its indications, from locally advanced to highly chemo-sensitive early-stage breast cancers. This shift aims to increase the use of conservative treatments instead of more invasive surgeries and to improve long-term outcomes. This paper describes our recent experience with the treatment of locally advanced inoperable breast cancer using moderate hypofractionated radiotherapy in combination with systemic therapy. Material/Methods: In 2023, more than 800 women with breast cancer were evaluated by a multidisciplinary team. Ten patients were deemed ineligible for surgery due to comorbidities or anesthetic risks and were considered for definitive radiotherapy. Four patients refused radiotherapy and opted for endocrine therapy only, while six patients received moderate hypofractionated radiotherapy. Treatment planning was performed using volumetric modulated arc therapy (VMAT). A total dose of 40.05 Gy in 15 fractions was delivered to the entire breast and nodal volume (levels I–IV). Concurrently, a tumor boost was given up to 52.5 Gy (3.5 Gy/fraction). One patient was treated with palliative intent, receiving 30 Gy in 10 fractions to the tumor site. The median follow-up was 9 months