[Extent of resection in patients with glioblastoma]. / Stepen' khirurgicheskoi rezektsii pri glioblastome.

OBJECTIVE: To investigate the impact of resection quality on subsequent survival of patients with glioblastoma. MATERIAL AND METHODS: There were 141 patients with morphologically confirmed glioblastoma (grade 4). Fractionation with the prescribed dose of 2 and 3 Gy was alternately used (pairwise modeling strategy). Total resection was performed in 29.8% of patients (EOR: 100%; n=42), subtotal - 56.7% (EOR: 70-99%; n=80). Extent of resection 1-69% was registered in 19 patients (13.5%). RESULTS: As of December 2022, 124 out of 141 patients (87.9%) were diagnosed with primary progression, 101 (71.6%) ones died. We analyzed the threshold role of EOR. The most informative level was 70% (p=0.002). EOR 100% was followed by median overall survival about 32.2 months (95% Cl: 15.3-49.1), EOR 70-99% - 21.3 months (95% Cl: 15.1-27.5), EOR 1-69% - 10.3 months (95% Cl: 3.8-16.9; p=0.003). Fractionation mode with the prescribed dose of 3 Gy partially eliminated significance of EOR (p=0.148) in contrast to standard fractionation (p=0.015). Tumor growth in the interval between surgery and radiotherapy (REP) reduces significance of EOR (p=0.042). Inclusion of second-line therapy with bevacizumab in multivariate analysis model (OR=0.488; p=0.002) makes EOR less significant (OR=0.749; p=0.085) in contrast to REP (OR=2.482; p<0.0001). CONCLUSION: To date, the principle of maximum safe resection remains fundamental in neurosurgery. EOR about 70% is sufficient regarding overall survival, but total resection should be sought if possible.

[Early progression of glioblastoma before radiotherapy]. / Rannee progressirovanie do luchevoi terapii pri glioblastome.

OBJECTIVE: To analyze the influence of continued growth of glioblastoma between surgery and radiotherapy on subsequent survival. MATERIAL AND METHODS: Fractionation with a prescribed dose of 2 and 3 Gy was alternately applied using a pairwise modeling strategy in 140 patients with morphologically confirmed glioblastoma (grade 4). Early progression of disease between microsurgery and radiotherapy was diagnosed in 60 patients, and no tumor growth was noted in 80 patients. RESULTS: The minimum period of early progression was 0.33 months, maximum - 4.27 months (median 1.1 (95.0% CI: 0.9-1.3)). The most significant predictors of early progression were resection quality (p<0.0001), large residual tumor (p=0.003) and no MGMT promoter methylation (p=0.001). IDH1 status did not affect early progression. In residual tumor ≥1.2 cm3, the median period of early progression was 1.9 months (n=70; 95% Cl: 1.3-2.5), <1.2 cm3 - 3.5 months (n=70; p=0.019). After resection of less than 76% of tumor, this value was 1.1 months (n=28), ≥76% - 3.1 months (n=112; p=0.006). Without tumor growth, the median overall survival was 33.41 months (n=80; 95% Cl: 27.1-39.7), with early progression - 16.03 months (n=60; 95% Cl: 13.5-18.6; p<0.0001). This predictor was significant for fractionation with a prescribed dose of 3 Gy (p<0.0001) and standard radiotherapy (2 Gy; p=0.028). By December 2022, 26 out of 40 patients without early progression survived two years after treatment (3 Gy) (65%, median not reached). In case of fractionation with a prescribed dose of 2 Gy, 20 patients survived this period (50%, median reached). CONCLUSION: Almost half of patients with newly diagnosed glioblastoma develop early progression between microsurgery and radiotherapy. Therefore, patients with and without early progression should be probably assigned to different prognostic groups regarding overall survival.