В систематическом обзоре о роли и развитии гипофракционной лучевой терапии (HFRT) в качестве возможной терапевтической стратегии у пациентов с глиобластомой (GBM) отмечено, что прогноз при GBM остается плохим, использование гиперфракционирования и эскалация дозы за 60 Гр не привели к улучшению показателей выживаемости. В качестве нового подхода стали использовать HFRT, получены интересные результаты. В большинстве работ, опубликованных с 1990 г., отмечено

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Hypofractionation has the dual advantage of increased cell death with a higher dose per fraction and a reduced effect of accelerated tumor cell repopulation due to a shorter overall treatment time. However, the potential advantage may be offset by increased toxicity in the late-responding neural tissues. Recently, investigators have attempted delivering radical doses of HFRT by escalating the dose in the immediate vicinity of the enhancing tumor and postoperative surgical cavity and reported reasonable outcomes with acceptable toxicity levels. Three different studies of high-dose HFRT have reported on the paradoxical phenomenon of improved survival in patients developing radiation necrosis at the primary tumor site. The toxicity criteria of RTOG and EORTC have defined clinically or radiographically suspected radionecrosis as Grade 4 toxicity. However, most patients diagnosed with radiation necrosis in the above studies remained asymptomatic. Furthermore, the probable association with improved survival would strongly argue against adopting a blind approach for classifying radiation necrosis as Grade 4 toxicity. The data emerging from the above studies is encouraging and strongly argues for further research. However, the majority of these studies are predominantly retrospective or relatively small single-arm prospective series that add little to the overall quality of evidence. Notwithstanding the above limitations, HFRT appears to be a safe and feasible strategy for glioblastoma patients.

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Purpose: Assessment of the effect of homogeneous distribution inside the radiation target on local control in glioblastoma. Material and methods: In patients under the age of 50, fractionation with the prescribed dose of 2 and 3 Gy was alternately used: the first patient was prescribed a regimen with a dose of 3 Gy, the next – with a dose of 2 Gy (a study involving a pairwise selection strategy). The same approach is used for the older age group (50 years and more). A total of 141 patients had morphologically confirmed glioblastoma (grade 4). 10 patients who had not completed a full course of radiation therapy were excluded. Additionally, 27 patients with GBM were added, treated in the experimental study of National Medical Research Radiological Centre without methodological features. In total, 158 patients were included in the study. 74 patients were treated with the prescribed dose of 2 Gy, 84 had a dose of 3 Gy. Results: The median homogeneity index in our study was 7.5 (95% Cl: 6,7-8,3). The minimum HI indicator was at the level of 2.5, the maximum – 36.9. We managed to identify the most informative level of the homogeneity index according to the criterion of local control. The median disease-free survival in the group with HI>=8.5 was 7.9 months (n=62; 95 % Cl: 1.6-14.2), in the group with a lower level of homogeneity - 5.4 months (n=96; p=0.024). The significance of the highlighted HI range depended on the fractionation mode used. The median relapse–free survival with fractionation of 3 Gy in the group with HI>=8.5 was 12.7 months (n=38), in the group with a lower level of homogeneity - 8.3 months (n=46; p=0.020). In the group with fractionation regime of 2 Gy: 6.4 and 3.8 months, respectively (n=24/50; p=0.336). The median overall survival in the group with HI>=8.5 was 27.2 months, in the group with a lower level of homogeneity – 21.2 months (p=0.904). Conclusion: The level of homogeneity has no significance according to the criterion of overall survival. Despite the fact that this predictor is of value only in scientific terms, the fact of its influence on local control allows to continue research in this direction. This primarily concerns the fractionation regimen with a prescribed dose of 3 Gy.