Stereotactic radiosurgery of recurrent malignant gliomas

Abstract

High-grade gliomas (HGG) are the most aggressive primary neuroepithelial tumors. In this group of patients, high mortality rates persist, and the median survival rate fluctuates around 24.5 months. In order to clarify the issue of choosing adequate doses of the necessary stereotactic radiosurgery (SRS), as well as to elucidate the factors affecting the effectiveness of radiosurgical treatment, we have undertaken this study. The N.V. Sklifosovsky Clinical and Research Institute for Emergency Medicine uses SRS on the gamma knife device, which is a successful combination of surgical and radio-oncological treatment technologies. All patients underwent SRS procedure with a relapse of HGG. The prescribed dose was in the range of 10–24 Gy. In all cases, before SRS, in addition to MRI in T1 mode with contrast enhancement, PET-CT with amino acids (11C-methionine, 18F-fluoroethylthyrosine) was also performed. The median overall survival for the entire HGG group from the date of surgical treatment was recorded at the level of 23,66 months, the median overall survival after SRS was 13,51 months, relapse-free survival after SRS for the entire HGG group was noted at the level of 7,1 months. Radiation toxicity was observed in 16,33 % of cases. SRS is a promising method of choice in a case of small local and distant relapses of HGG, allowing for a fairly long period of time to control the progression of the disease while maintaining a high quality of patients’ life. Meanwhile, the minimum of pronounced toxic effects of SRS makes it possible to use it repeatedly, up to a significant volume of tumor relapse.