ESTRO 2025 - Abstract Book

S580

Clinical - Breast

ESTRO 2025

Conclusion: The results of doses to cardiac substructures in our study is coherent with those described in literature (3-4). These results do not reflect any statistical signification between dosimetric parameters in cardiac substructures and the cardiac events, maybe due to the low number of events in our cohort. In our experience, UHF in breast cancer is safe, and is not related with a higher risk of cardiac event, with minimal toxicity, excellent cosmetic outcome and a low number of local failures.

Keywords: ultra-hypofractionation, cardiotoxicity

References: 1. Bergom C, et al. Past, Present, and Future of Radiation-Induced Cardiotoxicity: Refinements in Targeting, Surveillance, and Risk Stratification. JACC CardioOncol. 2021 2. Jacobs JEJ, et al. Mortality and Major Adverse Cardiac Events in Patients With Breast Cancer Receiving Radiotherapy: The First Decade. J Am Heart Assoc. 2023 3. Naimi Z, et al. Cardiac substructures exposure in left-sided breast cancer radiotherapy: Is the mean heart dose a reliable predictor of cardiac toxicity? Cancer Radiother. 2021 4. Altınok A, et al. Dosimetric evaluation of right coronary artery in radiotherapy for breast cancer. Med Dosim. 2019

3501

Digital Poster Initial brain metastasis velocity in breast cancer patients – Does volume matter? Katharina Hintelmann 1 , Maximilian Grohmann 1 , Schohla Wahaj 1 , Tobias Gauer 1 , Kerstin Borgmann 2 , David Krug 1 , Cordula Petersen 1 1 Department of Radiotherapy and Radiation Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. 2 Laboratory for Radiobiology and Experimental Radiooncology, University Medical Center Hamburg Eppendorf, Hamburg, Germany Purpose/Objective: The initial brain metastasis velocity (iBMV) is a prognostic metric introduced for patients receiving stereotactic radiosurgery (SRS) for brain metastases (BM), reflecting intracranial disease dynamics [1, 2]. It accounts for the number of BM at the time of first SRS divided by time since the initial primary cancer diagnosis. Here we analysed a volume-based iBMV (v-iBMV) in a subcohort of patients with breast cancer brain metastases (BCBM) to assess its prognostic value. Material/Methods: We conducted a retrospective, single center cohort study of 92 BCBM patients who received radiotherapy to the brain between 01/2013 and 12/2020. v-iBMV was defined as the volume of intracranial disease at first diagnosis of BM, divided by the time interval (in units of years) since the initial diagnosis of breast cancer. Volume of BM was available for 30 patients and therefore calculated for this subcohort. Non-volumetric “classical” iBMV was calculated for comparison.