S2580
Radiobiology – Normal tissue radiobiology
ESTRO 2026
group and sex considering skin reactions within 30 days post irradiation (figure). For proton doses up to 26 Gy, the average skin toxicity score was below 0.5 for both sexes and proton dose rates. At higher doses, female mice express a higher skin toxicity score, an effect that diminishes at the maximum dose. Moreover, reduced skin reactions were observed for mice treated at higher proton dose rate, independent on sex.
Digital Poster 3771 Sex matters (in skin radiation response)
Manuel Bernabei 1,2 , Felix Horst 2,3 , So ň a Michlíková 2,3 , Jörg Pawelke 2,3 , Moritz Schneider 1,3 , Michael Schürer 4,3 , Marielle Wolf 1,3 , Mechthild Krause 5,6 , Antje Dietrich 5,3 , Elke Beyreuther 1,3 1 Institut of Radiation Physics, Helmholtz-Zentrum Dresden - Rossendorf, Dresden, Germany. 2 Institut of Radiation Oncology - Oncoray, Helmholtz-Zentrum Dresden - Rossendorf, Dresden, Germany. 3 Oncoray - National Institute of Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus- Technische Universität Dresden- Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany. 4 National Center for Tumor Diseases Dresden (NCT/UCC), Germany: German Cancer Research Center (DKFZ), Heidelberg, Germany;, Faculty of Medicine and University Hospital Carl Gustav Carus, TUD Dresden University of Technology, Dresden, Germany; Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany. 5 German Cancer Consortium (DKTK), Partner Site Dresden, and German Cancer Research Center (DKFZ), Heidelberg, Dresden, Germany. 6 Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany Purpose/Objective: In an ongoing tumour control study, the influence of proton dose rate on the radiation response of human head and neck (hHNSCC) tumour xenografts is investigated. Beside tumour response, normal tissue reactions are recorded providing the possibility to analyse potential gender specificities. Material/Methods: Three hHNSCC tumour models were transplanted in female and male (50/50) NMRI nude mice and irradiated in a 225 MeV spread-out Bragg peak at a defined tumour diameter. The animals were treated with increasing proton doses in the range of 14 – 48 Gy and proton dose rates of about 10 Gy/min and 100 Gy/s, respectively. Depending on the tumour model, the mice were followed for up to 150 days after irradiation including regular scoring of health status and skin reactions at least twice a week. Skin reactions were scored according to RTCOG grading from 0 (no skin reaction) to 3 (euthanasia criterion). Results: For two of three tumour models, the irradiations have been completed and follow-up is ongoing. Although the main endpoint (tumor control) cannot be analysed to date early skin reactions are recorded for all dose groups (113 male and 116 female mice) and both dose rate regimes. To analyse the gender specific response, the average skin toxicity score was calculated per dose
Average skin toxicity score for male (black) and female (red) mice treated with conventional (upper row) and Flash (lower row) proton dose rates; number of animals per group are given in brackets. Conclusion: The analyses of two-third of the planned animal trial reveal a gender specific higher radiosensitivity of female nude mice skin to proton irradiation at doses higher than 26 Gy. This result will be substantiated by data of the ongoing irradiation campaign of the third model and by associated late effects. Moreover, our preliminary results indicate a skin protecting effect of the higher proton dose rate compared to conventional treatment over minutes. This finding will also be completed by the third tumour model and the ongoing analysis of tumour control data. Keywords: gender related radiation response, proton, Flash Digital Poster 3894 Disrupted Endothelial–Smooth Muscle Communication Drives Radiation-Induced Vascular Remodeling Fang Zhao 1,2 , Julia Wiedemann 1,2 , Rob Coppes 1,2 , Peter van Luijk 1,2 1 Department of Radiation Oncology, University Medical Center Groningen, Groningen, Netherlands. 2 Department of Biomedical Science, University Medical Center Groningen, Groningen, Netherlands Purpose/Objective: Thoracic radiotherapy is a cornerstone treatment for lung cancer. However, it inevitably causes radiation damage to surrounding normal tissues, including the pulmonary vasculature[1], which may lead to cardiac dysfunction and even heart failure. Radiation induced
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