ESTRO 2025 - Abstract Book

S454

Clinical - Breast

ESTRO 2025

704

Digital Poster Hypofractionated breast radiotherapy according to the FAST-Forward scheme: excellent early tolerance or delayed skin reactions? Jihane BOUZIANE 1,2 , Pierre Loap 1 , Sofiane Allali 1 , Alain Fourquet 1 , Youlia Kirova 1 1 Radiation Oncology, Institute Curie, Paris, France. 2 Radiation Oncology, CHU HASSAN II, Fez, Morocco Purpose/Objective: Over the past 3 decades, the fractionation of radiation therapy for breast cancer has evolved, with a trend towards hypofractionated regimens. The FAST-Forward trial evaluated a radiotherapy protocol in five daily fractions, offering a potentially effective and more convenient alternative to conventional regimens. The primary objective of our study was to evaluate acute skin reactions in patients treated with hypofractionated adjuvant radiotherapy for breast cancer according to the FAST-Forward protocol, along with their time to onset. Material/Methods: This retrospective single-centre study included all patients treated for early breast cancer with radiotherapy according to the FAST-Forward regimen (26 Gy in 5 fractions). Follow-up was performed by clinical examinations and mammography; skin toxicities were assessed according to CTCAE v5 criteria. Results: Between December 2014 and December 2022, 255 patients were treated according to the FAST-Forward regimen (26 Gy in 5 daily fractions). The median age of patients was 76 years. Of these, 93.7% had invasive carcinomas, and 93.3% had tumours staged T1 or T2. Treatments were performed in supine position for 46.3% of patients and in isocentric lateral ddecubitus position for 53.7%. For acute dermal toxicities, acute radiodermatitis was observed in 35 patients (13.7%), mainly Grade 1, and 4 patients (1.6%) had Grade 2 radiodermatitis. Acute radiodermatitis occurred after a mean period of 1.6 months. Delayed toxicities were noted in 24 patients (9.4%), including oedema, persistent skin pigmentation, and breast fibrosis, 1.2% of which were Grade 2. No acute or delayed toxicity of grade 3 or higher was reported. Conclusion: The efficacy and good tolerance of the adjuvant breast irradiation regimen of 26 Gy in 5 fractions has already been proven. Monitoring of this homogeneous group of patients highlighted the possibility of delayed acute skin reactions. Further consultation during treatment seems necessary to diagnose and treat these reactions.

Keywords: FAST-Forward, Delayed toxicities, breast cancer

754

Digital Poster Adjuvant radiotherapy for male breast cancer: insights from a 35-year single-institutional cohort Luisa Bellu 1 , Carlo Alberto Giorgi 2 , Alessandro Parisi 1 , Sara Talomo 1 , Enrica Bovo 1 , Fabio Busato 3 , Francesca Porra 4 , Cristina Falci 2 , Giovanni Faggioni 2 , Tommaso Giarratano 2 , Eleonora Mioranza 2 , Federica Guida 5 , Massimo Ferrucci 6 , Federica Miglietta 4,2 , Maria Vittoria Dieci 4,2 , Francesco Pasqualetti 7,1 , Marco Krengli 7,1 , Valentina Guarneri 4,2 1 Division of Radiotherapy, Veneto Institute of Oncology IOV-IRCCS, Padua, Italy. 2 Division of Medical Oncology 2, Veneto Institute of Oncology IOV-IRCCS, Padua, Italy. 3 Division of Radiotherapy, Policlinico Abano, Abano Terme, Italy. 4 Department of Surgery, Oncology and Gastroenterology, University of Padua, Padua, Italy. 5 Medical Physics Department, Veneto Institute of Oncology IOV-IRCCS, Padua, Italy. 6 Division of Breast Surgery, Veneto Institute of Oncology IOV-IRCCS, Padua, Italy. 7 Department of Medicine, University of Padua, Padua, Italy

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