Stages of stereotactic radiosurgery in the treatment of recurrent glioblastomas

Abstract

Objective: to evaluate the effectiveness of stereotactic radiosurgery as a therapy method taking into account overall survival in patients with recurrent glioblastoma at all stages of treatment. Materials and methods. A sample of patients (66 ailments) who were treated in 2016-2021 with a molecularly confirmed diagnosis of wild-type glioblastoma was analyzed. Only patients, who, were treated in several stages and as a rule, underwent stereotaxic radiosurgery (SRS), or SRS alone after a biopsy, or SRS in case of relapse, after surgery and radiotherapy, or SRS for subsequent relapses were selected. When evaluating the results, the following were taken into account: 1) age at the diagnosis, 2) volume of surgical resection, 3) use of radiation therapy, 4) use of adjuvant chemotherapy after SRS and response evluation criteria in solid tumors. Overall survival (OS) was assessed after diagnosis and at the time of SRS. Results. Patients received SRS at an average 10 months after initial diagnosis. Median duration of follow-up was 8 months after SRS and 12 months after diagnosis, median OS for all patients was nine months (1 to 42 months) after SRS and 20 months (4 to 64 months) respectively. The median survival after SRS was 9 months (p=0.008; χ2=7.008). The median OS for younger patients (<50 years) was 32.5 months, for elderly patients (>50 years) was 14.8 months (p=0.04; χ2=3.870). The median overall survival rate was 32.2 months in patients who received SRS 10 months after the diagnosis was made, and 16 months in those who received SRS earlier than 10 months (p=0.004, χ2=8.145). Radiosurgical doses ≥15 Gy were correlated with a mean survival rate of nine months and seven months in patients treated at doses <15 Gy (p=0.01; χ2=6.756). In patients who received adjuvant therapy with bevacizumab and/or chemotherapy after SRS, the median OS was 12 months, in patients who did not receive additional therapy after SRS, it was 7 months (p=0.04, χ2=4.19). Conclusions. Stereotactic radiosurgery promotes the effectiveness of glioblastoma treatment due to the possibility of carrying out this method at various stages of treatment. The overall survival of our patients depended on the period of SRS after diagnosis, patient age, radiation dose, and adjuvant chemotherapy.