Global, regional, and national burden of brain and other central nervous system cancers from 1990 to 2021, and projections to 2035: a systematic analysis for the global burden of disease study 2021

Background: The burden of primary brain and other central nervous system (CNS) cancers, collectively termed CNS cancers, has undergone significant changes in recent decades. This study aimed to estimate the burden, trends, and inequalities of at the global, regional, and national levels from 1990 to 2021, as well as projections to 2035. Methods: We used 2021 Global Burden of Disease Study (GBD) data and methodologies to describe changes in the burden of CNS cancers from 1990 to 2021, including prevalence, incidence, mortality, and disability-adjusted life years (DALYs). Furthermore, the Autoregressive Integrated Moving Average (ARIMA) model was used to forecast the future CNS cancer burden until 2035. Finally, we conducted decomposition analysis to identify the key drivers of variation in CNS cancer burden. Frontier analysis was used to visually illustrate the potential for burden reduction in each country or region based on their development levels. Results: From 1990 to 2021, global cases of CNS cancers have increased in prevalence and incidence by 124.50% and 106.53%, respectively, with corresponding increases in related age-standardized rates (ASRs). A similar increase of the number was also observed in CNS cancer-related mortality and DALYs, accompanied by a decline in the ASRs of DALYs and a stable state in the ASRs of mortality. Sex and age data from the GBD 2021 demonstrated an exclusively older male predominance in CNS cancer-related ASRs of prevalence, incidence, mortality, and DALYs. In 2021, regions with a high Socio-Demographic Index (SDI) had the highest ASRs of prevalence, incidence, mortality, and DALYs. By 2035, the estimated global number of prevalent cases, incident cases, deaths, and DALYs is projected to be 1.22 million, 0.43 million, 0.31 million, and 10.27 million, with an increase of 24%, 19%, 19% and 15% from 2021 to 2035, respectively, though the ASRs of incidence and DALYs decreased to some extent. Decomposition analysis showed the major contributory roles of population growth and aging on the incidence, mortality, and DALYs, although epidemiological changes also contributed to the prevalence to some extent. Frontier analysis of 204 countries and regions indicated that a higher SDI was associated with higher CNS cancer-related ASRs of prevalence, incidence, mortality, and DALYs and that countries or regions with higher SDI levels tended to have greater potential for improvement. Conclusions: Life expectancy for individuals with CNS cancers has increased since the 1990s, coinciding with a substantial reduction in DALYs rate and a stable CNS cancer-related mortality rate. However, mortality and DALYs related to CNS cancers have been particularly high in men across all age groups, those residing in higher SDI regions, and older adults. Considering the continuous increase in the CNS cancer burden by 2035, efficacious management of CNS cancers continues to pose a substantial challenge, highlighting the need for more regionally tailored strategies and guidelines on the sex-specific treatment protocols for older males to alleviate the disease burden, which is largely driven by aging and population growth in different SDI regions.