Abstract PO5-22-05: ULTRA-HYPOFRACTIONATED ADJUVANT RADIATION THERAPY FOR BREAST CANCER (UK FAST FORWARD TRIAL): A REAL LIFE SCENARIO ANALYSIS IN A DEVELOPING COUNTRY

Abstract Introduction: Selected patients showed non-inferior outcomes after conservative surgery for early breast cancer in the FAST-Forward UK (26Gy in 5 fractions) when compared to standard to date treatment. This study triggered an important change in radiation therapy routines across the world. We aimed to establish a pattern of treatment related events at a third-world country cancer center. Methods: We retrospectively analyzed all patients treated with 26Gy in 5 fractions (1 week) from January 2020 to June 2023. All data was exported and analyzed for demographics. A clinical profile was traced, dosimetric parameters and side effects assessed based on individual inquiries to each patient, per and post treatment. A strict medical record was kept in order to understand patterns of side effects and results. Results: 101 individuals were identified. Mean age was 64 years, 48 (47%) patients experienced radiation dermatitis of any grade, 33 (32%) grade 1, 9 (8%) grade 2, 6 grade 3 or 4 (5%). Patients older than 60 years showed to be a significant factor for dermatitis development (34 over a total of 48 - 70%) and 8 (53%) over 15 had grade 2 or higher dermatitis. 27 (26%) developed radiation dermatitis during sessions. 21 (20%) took 7 or less days to heal; 27 (26%) had a recovery longer than one week at an average age of 65 years - being the majority of dermatitis grade 1. Reported toxicities were sharp pain 31 (30%), burning pain 24 (23%), edema 17 (16%) and pruritus 5 (4%). At the time of this study was completed, 3 reported deaths (2%) were reported - with a 97% rate of survival. Conclusions: The fast forward trial regimen has 3 years since its publication. Our study shows that in a selected group of breast cancer patients, this novel model has shown to be a safe alternative for adjuvant radiation therapy following breast conservative surgery, results corroborating with published data. To the best of our knowledge, this is the largest single center group analyzed and published. Citation Format: Renne Bart, Daniel Przybysz, Ramon Ferrari, Leonardo Franco, Carlos Almeida, Paulo Canary. ULTRA-HYPOFRACTIONATED ADJUVANT RADIATION THERAPY FOR BREAST CANCER (UK FAST FORWARD TRIAL): A REAL LIFE SCENARIO ANALYSIS IN A DEVELOPING COUNTRY abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-22-05.