Reirradiation of gliomas with hypofractionated stereotactic radiotherapy: efficacy and tolerance analysis at a single center.

Background: Recurrent high-grade gliomas present a therapeutic challenge. Repeat surgery, re-irradiation, and systemic therapy have been explored, with re-irradiation requiring precise tumor relapse delineation and advanced dosimetric techniques. This study aims to evaluate the effectiveness and tolerability of re-irradiation using Hypofractionated Stereotactic Radiation (HFSRT) schedules. Materials and methods: In a retrospective analysis from 2011 to 2021, 52 adult patients with recurrent high-grade gliomas were examined, including 42.3% with glioblastoma, 32.5% with grade 3 gliomas, and 25% with grade 2 gliomas as initial diagnosis. All received prior radiotherapy at doses ranging from 54-60 Gy, with a median time to tumor relapse of 19.8 months. Salvage surgery was performed in 42.3% of cases, with a median interval of 22.45 months between radiation courses. Re-irradiation doses were 30 Gy in 5 fractions for 54% and 40 Gy in 10 fractions for 46%. Concurrent systemic treatments included temozolomide (30.8%), nevacizumab (27%), or none (35%). Results: In-field and out-field tumor progression occurred in 65.4% and 25% of patients, with median times to local and distant progression of 5.17 and 4.57 months. Median overall survival (OS) from re-irradiation was 12 months. Univariate analysis showed a trend favoring 30 Gy in 5 fractions for disease progression-free survival (DPFS). Treatment was generally well-tolerated, with only 5.7% experiencing acute Grade-3 toxicity, and symptomatic radionecrosis occurred in 2 patients. Conclusion: Re-irradiation using HFSRT for recurrent high-grade gliomas is viable and well-tolerated, demonstrating survival rates comparable to existing literature. These findings underscore the potential of HFSRT in managing recurrent high-grade gliomas.