ESTRO 2025 - Abstract Book

S3969

Radiobiology - Tumour radiobiology

ESTRO 2025

the basal and TNBC subtypes showed the greatest benefit from moderate dose escalation, with over 90% of these patients achieving GARD > 21 with a theoretical 57 Gy boost in 15 fractions.

Conclusion: This study demonstrates the feasibility of using the RSI and GARD models to personalize radiotherapy dose escalation in breast cancer patients. Standard fractionation regimens generally achieve the desired biological effectiveness, while extreme hypofractionation requires significant dose escalation to match. These findings highlight the potential for personalized dose-escalated radiotherapy, especially in aggressive subtypes like TNBC. Prospective clinical validation is necessary to further explore the clinical utility of GARD-guided treatment strategies.

Keywords: GARD ; radiosensibility ; genetic signature

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Digital Poster Microbeam Radiation Therapy (MRT) and Minibeam Radiation Therapy (MBRT) improve local tumor control in a mouse tumor study Thomas E Schmid 1,2 , Manuel Bernabei 2 , Mabroor Ahmed 2 , Jessica Stolz 1 , Narayani Subramanian 2 , Aleksandra Colic 2 , Marina Franco 1 , Mariaelvy Bianchini 2 , Johanna Winter 1 , Susanne Raulefs 1 , Stefan Bartzsch 1 , Stephanie E Combs 1,2 1 Department of Radiooncology, School of Medicine and Health, Technische Universität München, München, Germany. 2 Department of Radiation Medicine (IRM), Helmholtz Zentrum München, Neuherberg, Germany Purpose/Objective: Microbeam Radiation Therapy (MRT) and minibeam radiation therapy (MBRT) are two innovative preclinical concepts in radiotherapy that collimates X-ray radiation in micrometer-wide, planar beams. Previous research has