Epidemiology of Glioblastoma in Kazakhstan: A 10-Year National Registry Cohort Analysis

Abstract

Glioblastoma (GBM), which was previously identified under the name of glioblastoma multiforme, is one of the most common and aggressive primary brain tumors. In the Unit ate States, the age-adjusted incidence rate of glioblastoma is 3.21 per 100,000 individuals annually. Glioblastoma is a non-curable disease associated with extremely poor survival; the median survival is about 12 months, and even worse in elderly patients, about 8.5 months. Life expectancy without any intervention (e.g., surgery, radiation, chemotherapy) is less than three months. This is a retrospective cohort study; data were obtained from the National Electronic Registry of Oncological Patients of the Republic of Kazakhstan from January 1, 2014, to December 31, 2023. All primary malignant brain tumors were initially identified using ICD-10 codes C71.0-C71.9. From this pool, only histologically confirmed glioblastoma cases were selected based on International Classification of Diseases for Oncology, Third Edition (ICD-O-3) morphology codes:9440/3(Glioblastoma, NOS), 9441/3(Giant Cell Glioblastoma), and 9442/3 (Gliosarcoma). For survival analysis, Kaplan–Meier methods were used to estimate survival probabilities, and the log-rank test was applied to compare survival curves across subgroups. Cox proportional hazards regression was used to identify factors associated with overall survival among adult glioblastoma patients. A total of 1531 glioblastoma cases were identified from 2014 to 2023. The age-adjusted incidence rate (ASIR) of glioblastoma during the study entire period was 1.05 per 100,000 overall, 1.15 per 100,000 in males, and 0.85 per 100,000 in females. The Kaplan–Meier survival analysis indicated that the median survival for glioblastoma was 7.52 months, and the survival probability was 39.88% at 12 months, declining to 9.99% at 60 months. This study presents the first national population-based estimates of glioblastoma incidence, prevalence, and survival in Kazakhstan (2014-2023). Further research incorporating molecular markers is recommended, which are crucial for precise tumor classification and prognostic stratification according to the recent WHO classification, and important clinical details such as comorbidities, to get a strong and more reliable estimation of the epidemiology of glioblastoma.