ESTRO 2025 - Abstract Book

S3927

Radiobiology - Normal tissue radiobiology

ESTRO 2025

as normal, with only 6 of 29 axons (21%) displaying grade 1 damage. In the bevacizumab group, 17 of 29 axons (59%) were normal, while 12 of 29 axons (41%) showed grade 1 or higher damage. Both the melatonin and bevacizumab groups demonstrated significantly reduced axonal damage grades compared to the sham group (p<0.001). Additionally, melatonin exhibited a trend toward enhanced neuroprotection, with lower axonal damage grades compared to the bevacizumab group; however, this difference did not reach statistical significance (p=0.07).

Conclusion: Intravitreal melatonin demonstrated efficacy comparable to bevacizumab in reducing radiation-induced retinopathy, with an encouraging trend toward enhanced neuroprotection. These findings position melatonin as a potential novel therapeutic for radiation retinopathy prophylaxis.

Keywords: bevacizumab, melatonin, retinopathy

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Mini-Oral Experimental parameters for normal tissue preservation in Pulsed Electron FLASH-RT: potential clinical implications Anouk Sesink 1 , Anet Valdes Zayas 1 , David Repáraz 1 , Walter-Reiner Geyer 2 , Preethi Devanand 1 , Luca Soutter 2 , Till Tobias Böhlen 2 , Ryan Paisley 2 , Raphael Moeckli 2 , Claude Bailat 2 , Jean Bourhis 1 , Fernanda Herrera 1 , Veljko Grilj 1 1 Radiation Oncology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland. 2 Institut de Radiophysique, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland