e14025 Background: The effectiveness of radiation therapy in the classical and stereotactic treatment regimens of the primary glioblastoma multiforme was analyzed and compared. Methods: 87 patients with primary glioblastoma multiforme were hospitalized during the study period. 17 patients of them were in the treatment group (stereotactic radiotherapy, dose per fraction 2 Gy, 60 Gy total dose, CTV 2.0 cm, PTV 0.1 cm - group 1), and 70 patients were in the control group (conventionally fractionated radiotherapy, dose per fraction 2 Gy, 60 Gy total dose, CTV 2.0 cm, PTV 0.5 cm - group 2). Patients of both groups were treated with alkylating agents as the third stage of complex treatment. MGMT methylation was evaluated by pyrosequencing. Results: The use of stereotactic radiation therapy allowed to conduct a full course of treatment without interruption, whereas in the second group, due to the development of adverse reactions, the course was interrupted for 7 patients (10%). The advantage of stereotactic radiation therapy was a less pronounced increase and rapid regression of neurological deficits during treatment, manifested by better local control for 6 months. Hypermethylation of MGMT was detected in 39% of glioblastoma cases and was not detected in non-tumor tissue. The presence of promoter methylation disrupts DNA repair and is associated with longer survival in glioblastoma patients receiving alkylating agents. Note that the median survival of patients with MGMT hypermethylation in the group 1 was 285 days (IQR = 323.75), and in the group without hypermethylation was significantly more than 338.5 days (IQR = 476) (p = 0.045). A similar trend was observed in the second group: in patients with hypermethylated MGMT, the median survival was 271 days (IQR = 337), the result is different from patients without hypermethylated MGMT – 342 days (IQR = 493) (p = 0.039). Conclusions: As a result, the application of the stereotactic approach of radiation therapy in the complex treatment of patients with glioblastoma and their classification by the MGMT methylation status with a cut-off point of 10% has the basis for improving the effectiveness and tolerability of radiation therapy and contributes to the overall survival of patients.

The article represents the first experience of using stereotaxic radiation therapy in hypofractionational mode and radiosurgery for metastatic brain lesions in the radiotherapy department of the Volgograd Regional Clinical Oncological Dispensary. The study involved 15 patients with secondary metastatic brain lesions by tumors of various localizations. Complete tumor regression was recorded in 4 (27 %) patients. In 10 (67 %) cases, a positive response was noted in the form of a decrease in tumor size from 50 to 20 %. No early radiation complications and deaths were detected during radiation therapy.