Global, regional, and national analysis of CNS cancers burden from 1990 to 2021 and forecast of disease trend over the next 25 years

Central nervous system (CNS) cancers are highly lethal and resource-intensive, imposing a substantial and uneven burden worldwide. Comparable long-term estimates of disease burden and future trends are needed to inform prevention strategies and health system planning across regions with different socioeconomic contexts. Data were obtained from the Global Burden of Disease (GBD) 2021 study covering 204 countries and territories from 1990 to 2021. We estimated incidence, prevalence, mortality, and disability-adjusted life years (DALYs) at global, regional, and national levels. Age-standardized rates were calculated using the GBD standard population to enable comparisons across populations with different age structures. Socio-demographic Index (SDI)-based analyses and inequality metrics were applied to assess socioeconomic disparities in disease burden. Decomposition analysis was used to quantify the contributions of population growth, population aging, and changes in age-specific rates to DALY trends. Bayesian age-period-cohort (BAPC) models were employed to project future burden under the assumption that historical trends continue. In 2021, CNS cancer accounted for 0.36 million (95% UI: 0.31-0.41 million) new cases and 0.26 million (0.22-0.30 million) deaths worldwide, resulting in 8.91 million (7.61-10.36 million) DALYs. From 1990 to 2021, the global age-standardized incidence rate increased from 3.75 to 4.28 per 1,00,000 population, whereas the age-standardized DALY rate declined by 11.97%, indicating improved survival and disease management despite rising case numbers. Global prevalence increased from 4,34,000 in 1990 to 9,75,000 in 2021, reflecting the growing cumulative burden of individuals living with CNS cancer. Marked socioeconomic gradients were observed: high-SDI regions generally showed higher incidence rates but lower DALY rates, whereas low- and low-middle-SDI regions bore a disproportionate share of disability and premature mortality. Decomposition analysis indicated that population aging and population growth were the primary drivers of increasing DALYs, partially offset by reductions in age-specific rates. The global burden of CNS cancer is increasing, with marked socioeconomic disparities. These results are descriptive and scenario-based and should be interpreted in light of the assumptions and limitations of the GBD framework.