Trends, age shifts, and potential delayed peaks post-pandemic of early-onset brain and central nervous system cancers in individuals aged 20-49: a cross-sectional study

Central nervous system (CNS) cancers are highly lethal and increasingly affect younger populations aged 20-49, posing significant challenges to global healthcare systems. Current research on early-onset CNS cancer trends is limited and outdated, with uncertain impacts from the COVID-19 pandemic. This study explores the epidemiology of early-onset CNS cancer and the pandemic's effects. We analyzed incidence, mortality, and Disability-Adjusted Life Years (DALYs) rates for early-onset CNS cancer (ages 20-49) from 2019 to 2021 using GBD 2021 data. The global data were categorized into five regions based on the Socio-Demographic Index (SDI), reflecting income, education, and fertility rates. Trends over the past 30 years were examined using Estimated Annual Percentage Change (EAPC), Average Annual Percentage Change (AAPC), and Joinpoint analysis, with a focus on 2019-2021. The Bayesian Age-Period-Cohort (BAPC) model predicted post-pandemic impacts on CNS cancer metrics. In 2021, global cases of early-onset CNS cancer rose to 50,201.7 (95% UI, 42,864.1-58,187.5), with deaths increasing to 25,023.1 (95% UI, 20,973.8-29,670.8) and DALYs reaching 1,483,019.4 (95% UI, 1,240,923.4-1,756,043.3). The incidence rate increased to 2.1 (95% UI, 1.8-2.5), while mortality rates remained stable at 1.1 (95% UI, 0.9-1.2), and DALY rates decreased to 62.6 (95% UI, 52.4-74.1). Over the past two decades, the incidence of early-onset CNS cancer has steadily increased, particularly in regions with a high SDI and in emerging economies. Although there was a decline in early-onset CNS cancer-related metrics during the pandemic, it is anticipated that global incidence rates will peak between 2035 and 2040. This study provides a comprehensive overview of early-onset CNS cancer trends. Despite stable mortality rates, the increasing incidence suggests a growing global burden, with a delayed peak expected due to the pandemic. These findings highlight the need for preventive and control policies targeting early-onset CNS cancer.