ESTRO 2024 - Abstract Book

S5394

Radiobiology - Tumour biology

ESTRO 2024

1968

Digital Poster

Unraveling radiobiology of radiosurgery: initial insights from GL261 mouse model

Anastasia Janas 1,2,3 , Carolin Senger 3,4 , Kiril Krantchev 1,3 , Sanaria Al-Rubaiey 1,3 , Jan Bukatz 1,3 , Melina Nieminen-Kelhä 1 , Susan Brandenburg 1 , Irina Kremenetskaia 1 , Susanne Mueller 5,6 , Daniel Zips 3,4 , Peter Vajkoczy 1 , Güliz Acker 1,3,4 1 Charité-Universitätsmedizin Berlin (Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health), Department of Neurosurgery, Berlin, Germany. 2 Berlin Institute of Health, -, Berlin, Germany. 3 Charité-Universitätsmedizin Berlin (Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health), Department of Radiation Oncology, Berlin, Germany. 4 Charité Universitätsmedizin Berlin (Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health), Charité- CyberKnife Center, Berlin, Germany. 5 Charité-Universitätsmedizin Berlin (Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health), Department of Experimental Neurology and Center for Stroke Research, Berlin, Germany. 6 Charité-Universitätsmedizin Berlin (Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health), NeuroCure Cluster of Excellence and Charité Core Facility 7T Experimental MRIs, Berlin, Germany

Purpose/Objective:

Stereotactic radiosurgery (SRS) is an established clinical treatment for intracranial tumors, often integrated into combination therapies. While the outcomes of standard radiotherapy are defined within the 6Rs framework, theradiobiological effects, especially in the long-term, of high-dose irradiation on tumors, their microenvironments, and adjacent healthy tissue remain less elucidated. Therefore, this study seeks to comprehensively characterize SRS radiobiology over short- and long-term periods.

Material/Methods:

GL261 cells (20,000) were implanted into striatum of C57BL6/N mice (d0). Animals received either 20 or 40 Gy (n=24 per dose) SRS in a single dose on day 14, non-irradiated mice were controls (n=6 per dose). MRI investigations were carried out on d13 after implantation (prior SRS) and after SRS (d7, d30, d90, d180) using a 7T MRI scanner. At each specified timepoint, a subset of mice (n = 6 per group per timepoint) was sacrificed for histological evaluation, emphasizing proliferation (Ki67), apoptosis (TUNEL), and accumulation of tumor-associated macrophages as indicators of neuroinflammation and immune activation (TAMs /Iba1). Subsequent analyses used data from 4 mice per dose and timepoint. Statistical evaluations involved one-way ANOVA with a Bonferroni correction for tumor size variations over time, and a Student's T-Test for histological assessment.

Results: