Analysis of the overall survival of patients with primary glioblastoma of the brain depending on glial fibrillary acidic protein content in blood serum

Introduction. Glioblastoma is one of the most aggressive malignant brain tumors characterized by low sensitivity to drug therapy, frequent recurrence after surgical removal of the tumor, and an extremely unfavorable prognosis.

Aim. To analyze the overall survival of patients with primary glioblastoma of the brain based on the glial fibrillary acidic protein (GFAP) content of in blood serum.

Material and methods. 176 patients with primary malignancy grade IV glioblastoma confirmed by morphological and molecular genetic studies (99 men and 77 women) aged 18–82 years who underwent examination and treatment at the N.N. Blokhin National Medical Research Center of Oncology in the period from 2013 to 2024 were enclosed in the study. GFAP concentration in the pre-treatment blood serum was determined by enzyme immunoassay using Human GFAP ELISA kit (Biovendor, Czech Republic). The obtained data were processed using Statistica 10 (StatSoft) and SPSS (IBM) programs. Overall survival analysis was performed using the Kaplan–Meier method with the log-rank test for comparisons. Differences were considered statistically significant at p < 0.05.

Results. 72 of 176 patients were alive at the end of the study, the median follow-up period being 7.8 months, while 104 patients with died within a period of 1 to 103 months the median survival being 9.1 months. The median lifespan of all patients with glioblastoma was 14.8 months. 1-year overall survival rate comprised 56.7±4.2%, 2-year – 39.2±4.3%, 3-year – 30.0±4.1%, 4and 5-year – 26.8±4.0%, 10-year – 15.0±4.4%. The risk of death in patients with primary glioblastoma of the brain was the greatest in the first two years of follow-up from the time of diagnosis. No associations were found with patients’ age and gender, or the side of the tumor lesion. To study the relationship between long-term treatment results and serum GFAP concentrations patients were divided into two groups: 1) patients in whom GFAP was not detected (GFAP-negative) and 2) those with detectable GFAP concentrations (GFAP-positive). Median survival time of 46 GFAP-negative glioblastoma patients was 24.8 months, while in 130 GFAP-positive patients it comprised only 13.7 months (p = 0.047). No differences in the overall survival in GFAP-positive glioblastoma group depending on the serum GFAP concentration were found. The differences in the overall survival depending on the presence or absence of GFAP in blood serum were mostly pronounced in the female group and in patients below 50 years of age. Thus, median survival of GFAP-negative glioblastoma patients below 50 years was several fold higher than in GFAP-positive patients of this age group (70.8 and 12.4 months respectively).

Conclusion. The overall survival of patients with grade IV primary glioblastoma is significantly higher in GFAP-negative than in GFAP-positive group. Hence, the presence of GFAP in blood serum can be regarded as an unfavorable prognostic factor for this disease.