Objective: to evaluate the impact of extent of resection (EOR) and continued tumor growth in the early period after microsurgical intervention on subsequent radiation therapy. Subjects and methods. Seventy patients with verified high-grade glioma were treated in 2013 to December 2016. Improved imaging techniques, intraoperative neurophysiological mapping, a better understanding of cortical and subcortical anatomy, intraoperative methods to determine the tumor, including optical aids, made their contribution to the achievement of the maximum resectability. The new EOR threshold for glioblastomas is 70%; it has previously been considered that the EOR threshold is in the range between 78 and 100%. Results. Mortality in the control (0—69% EOR) group was 2.1 times higher than in the 98—100% EOR group (p=0.057) and 2.4 times higher than in the subtotal removal (70—95% EOR) group (p=0.007). However, the data of multivariate analysis completely level off the significance of EOR in terms of the overall survival criterion (p=0.614). The risk factors depreciating the importance of EOR were individual levels of LQ (dose: <60 Gy≥) with α/β=8.5 (p=0.000), the use of bevacizumab as second-line treatment (p=0.000), and age (<50 years≥; p=0.002). The median survival was 10.3 months in the group with signs of continued tumor growth after microsurgical intervention and 16.5 months in the non-progression group (p=0.026); however, the data of multivariate analysis, as with EOR, level off the significance of continued growth factor (p=0.602). Conclusion. The good functional status of patients after microsurgical intervention and the minimal radiological target that allows one to sum up conditionally radical doses in terms of the conventional offsets are valuable to a radiologist. The EOR threshold of 70% or more and continued tumor growth with a good functional status do not affect the quality of subsequent radiotherapy.