Breast cancer burden among women of reproductive age in China, Japan, and South Korea, 1990-2021: a systematic analysis from the Global Burden of Disease Study 2021.

[BACKGROUND] Breast cancer is the most common cancer among women globally, with incidence rates rising annually. However, systematic comparative studies on the burden of breast cancer among women of reproductive age in East Asian countries are currently lacking.

[METHODS] This study utilized the Global Burden of Disease (GBD) 2021 database to extract incidence, prevalence, mortality, disability-adjusted life years (DALYs) for breast cancer among women of reproductive age in China, Japan, and South Korea. Cross-national comparisons were conducted using age-standardized rates (ASR), and estimated annual percentage change (EAPC) and average annual percentage change (AAPC) were calculated. Joinpoint regression analysis identified trend turning points, and ARIMA models projected trends for 2022-2036.

[RESULTS] From 1990 to 2021, China, Japan, and South Korea exhibited upward trends in age-standardized incidence rates (ASIR) and age-standardized prevalence rates (ASPR) for breast cancer (ASIR: China's EAPC = 2.17, Japan's EAPC = 0.93, South Korea's EAPC = 3.86). Age-standardized mortality rates (ASMR) and age-standardized DALYs rates (ASDR) generally declined in China and Japan but increased in South Korea (ASMR: China's EAPC = -1.10, Japan's EAPC = -0.64, South Korea's EAPC = 0.11). Projections for the next 15 years indicate rising ASIR and ASPR in China, declining trends in Japan, and stabilization in South Korea; overall declines in ASMR and ASDR across all three countries.

[CONCLUSION] The findings emphasize the importance of enhanced, country-specific screening and prevention efforts for breast cancer among reproductive-age women in East Asia to address disparities in disease burden and early detection.