[Radiosurgery for recurrent glioblastoma].

Background: Despite the combined treatment in accordance with modern standards, recurrent glioblastoma usually occurs within several months after resection and causes low relapse-free and overall survival. One of the most effective methods for malignant glioma progression is repeated radiotherapy. Indications for this approach have expanded after introduction of stereotactic irradiation into routine clinical practice.
Objective: To evaluate the results of radiosurgery in patients with recurrent glioblastoma and to identify the factors determining its effectiveness.
Material and Methods: Radiosurgery has been carried out in 168 patients with relapses of glioblastoma between 2005 and 2021. This study enrolled 88 patients with 180 foci of local and distant progression. Mean age of patients was 42.8±2.1 years (range 4-73). Mean period between diagnosis and repeated irradiation was 12.7 months. Mean volume of focus was 2.4 cm ³ , mean dose - 20 Gy. Median follow-up period after radiosurgery was 11.2 months.
Results: Repeated irradiation with correction of systemic therapy improved progression-free survival and overall survival with insignificant radiation-induced toxicity. Annual overall survival was 62.2%, median of overall survival after radiosurgery - 15.1 months. Significant factors of local control were marginal dose of at least 18 Gy and distant relapse. Median of progression-free survival in the group of distant progression of glioblastoma was only 3.6 months vs. 9.1 months in patients with local recurrence.
Conclusion: Repeated irradiation in radiosurgery mode with a dose of 18 Gy and higher is an effective option for local treatment increasing progression-free and overall survival in patients with progression of glioblastoma.