Global burden and temporal trends of kidney cancer among children from 1990 to 2021: an analysis with projections to 2036.

Background: Childhood kidney cancer (KC), the third most prevalent pediatric solid malignancy, remains incompletely characterized in terms of epidemiological patterns and health inequities. This study aimed to analyze global trends, inequalities, and future burden of childhood KC from 1990 to 2021. Methods: Data on incidence, mortality, and disability-adjusted life years (DALYs) of KC among children aged 0-14 years were obtained from the Global Burden of Disease study 2021. Data from 1990 to 2021 were comprehensively analyzed by sex, location, age, and socio-demographic index (SDI), incorporating estimated annual percentage change, joinpoint regression, slope index of inequality and concentration index for inequality assessment, and Bayesian age-period-cohort forecasting. Results: In 2021, there were 9,576 incident cases, 3,063 deaths, and 268,049 DALYs globally due to childhood KC, with corresponding age-standardized incidence rate (ASIR), mortality rate (ASMR), and disability-adjusted life years rate (ASDR) of 0.48, 0.15, and 13.32, respectively. From 1990 to 2021, the global burden of childhood KC declined overall. Joinpoint regression identified a steeper decline in the most recent period, with the ASIR decreasing by 4.87% per year from 2018 to 2021 and the ASMR and ASDR decreasing by 5.12% and 5.23% per year, respectively, from 2019 to 2021. The decline in disease burden has been more pronounced in females than in males. The burden of childhood KC was mainly concentrated among children aged 0-4 years, whose age-specific incidence, mortality, and DALY rates were generally higher than those among children aged 5-9 years and 10-14 years. While no significant association was observed between SDI and ASIR, SDI exhibited a negative correlation with ASMR and ASDR. Inequality metrics showed that childhood KC mortality and DALYs were disproportionately concentrated in lower-SDI countries, and these disparities widened over time. Projections indicate continued declines in incidence and mortality for both sexes over the next 15 years. Conclusions: Over the past three decades, the burden of childhood KC significantly reduced, yet the rising incidence in lower-income regions warrants attention. Health inequities, characterized by a disproportionate concentration of the disease burden in low-SDI countries, have intensified. Enhanced understanding of pediatric KC epidemiology may aid in its prevention and management.