Epidemiological trends of burden of brain and CNS cancer at global, regional, and national level: a trend analysis study from 1990 to 2021.

BACKGROUND: Brain and central nervous system (CNS) cancers, though relatively rare, contribute substantially to neurological disability and cancer-related mortality worldwide. This study systematically assessed their global, regional, and national trends from 1990 to 2021 and projected burden through 2035 using Global Burden of Disease Study (GBD) 2021 data. METHODS: Using data from the Global Burden of Disease (GBD) 2021 study, we estimated age-standardised incidence rate (ASIR), prevalence rate (ASPR), death rate (ASDR), and DALY rate across 204 countries, 21 regions, and five socio-demographic index (SDI) groups. Trends were analyzed using estimated annual percentage change (EAPC), and future projections were generated using a Bayesian age-period-cohort (BAPC) model. RESULTS: From 1990 to 2021, the global ASIR of brain and CNS cancers increased from 3.75 (95% UI 3.21-4.21) to 4.28 (95% UI 3.71-4.88) per 100,000, with an EAPC of 0.45 (95% CI 0.40-0.49). ASPR rose from 8.66 (95% UI 7.55-9.53) to 12.01 (95% UI 10.54-13.52), while ASDR remained stable, and DALY rates declined from 119.88 (95% UI 99.23-137.57) to 107.91 (95% UI 91.74-125.59). High-income Asia Pacific showed the largest ASIR increase (EAPC 2.02), while Central Asia experienced the highest rise in DALYs (EAPC 1.20). Age and sex disparities were notable, with older adults (≥ 70 years) and males exhibiting higher rates. Projections indicate continued ASIR and ASPR growth, while ASDR and DALY rates decline, and-critically-an increase in the absolute numbers of cases, deaths, and DALYs through 2035 driven by population growth and ageing. INTERPRETATION: Brain and CNS cancers show increasing incidence and prevalence globally, with stable mortality and declining DALYs. These trends highlight the need for enhanced early detection, equitable access to care, and targeted interventions across regions. Notwithstanding broadly stable or declining age-standardised rates, absolute counts of cases and deaths are projected to rise to 2035, underscoring the urgency of scaling diagnostic and treatment capacity-particularly in lower-SDI settings.