S365
Clinical - CNS
ESTRO 2026
radiation necrosis was 7% (95% CI: 4 – 10%, I2=0.00%, p=0.93, Figure 2). Rates of other acute and chronic adverse events of any grade were 23% (95% CI: 18 – 29%, I2=33.63%, p=0.17) and 17% (95% CI: 12 – 22%, I2=63.97%, p=0.01). High-grade toxicity was rare. There was a considerable degree of reporting heterogeneity and a notable risk of bias for all studies.Figure 1.
doi: 10.1016/j.neuroimage.2012.02.084.[4] H. G. Pemberton et al., Sci. Rep., vol. 13, no. 1, p. 18911, Nov. 2023, doi: 10.1038/s41598-023-44794-0. Keywords: glioblastoma, hypofractionation, segmentation
Poster Discussion 1746
Rinse and repeat? The role of reirradiation in meningiomas – A systematic review and meta- analysis Erik Lutze 1 , Johanna von Pölnitz 1 , Jonathan P.S. Knisely 2 , Jana Ivanidze 3 , Anna M.E. Bruynzeel 4 , Joost J.C. Verhoeff 4 , Helen A. Shih 5 , Felix Ehret 6 1 Radiation Oncology, University of Hamburg, Hamburg, Germany. 2 Radiation Oncology, Weill Cornell Medical College, New York, USA. 3 Radiology, Weill Cornell Medical College, New York, USA. 4 Radiation Oncology, Amsterdam UMC, Amsterdam, Netherlands. 5 Radiation Oncology, Massachusetts General Hospital, Purpose/Objective: Meningiomas are the most common primary brain tumors in adults. Surgery and radiation therapy are the main treatment options and often achieve initial tumor control. However, tumor progression and local recurrence represent significant challenges, particularly in World Health Organization (WHO) grade 2 and 3 meningiomas. Reirradiation is a potential treatment option in such cases, but its outcomes are poorly defined. This systematic review and meta- analysis evaluates the role of reirradiation in meningiomas. Material/Methods: Outcome data regarding local control, overall survival, adverse events, and radiation necrosis after Boston, USA. 6 Radiation Oncology, Charité - Universitätsmedizin Berlin, Berlin, Germany reirradiation were analyzed. Only studies exclusively reporting on patients undergoing reirradiation for meningioma were included. The review and analyses follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Results: In total, 1350 publications were screened, and 16 studies with 385 patients were included. The median interval between initial radiation therapy and reirradiation was 40 months. Patients were reirradiated with stereotactic techniques (226 patients) or fractionated radiation therapy (125 patients, 78.4% particle therapy). Treatment details were unclear for 34 patients. The local control rate after reirradiation was 53% (95% confidence interval (CI): 48 – 58%, I2=4.39%, p=0.40, Figure 1), with an overall survival rate of 73% (95% CI: 68 – 78%, I2=0.00%, p=0.94), after a median follow-up of 32 months. The rate of any
Figure 2.
Conclusion: The limited data from the reviewed studies suggest that reirradiation can be a safe and effective treatment option. The profound heterogeneity of available studies, regarding but not limited to treatment techniques, intervals between treatments, WHO grades, target volumes, fractionation, and toxicity reporting, hinders the ability to clearly identify patient subgroups that benefit most from reirradiation. Further studies, prospective registries, and trials in particular, are warranted to assess the efficacy and safety of reirradiation in meningioma. Keywords: Meningioma, Reirradiation, Systematic review
Mini-Oral 1755
Dose escalation with intensity-modulated proton therapy for high-risk meningiomas – Results from a phase 1 trial Felix Ehret 1 , Nora K. Horick 2 , Beow Y. Yeap 2 , William T. Curry 3 , Brian Nahed 3 , Juliane Daartz 1 , Jason M.
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