Breast cancer trends in China and its comparative analysis with group of 20 countries: Projections for 2022–2040

BACKGROUND: Breast cancer is the most commonly diagnosed cancer among women worldwide. This study analyzed and compared breast cancer patterns in China and the Group of 20 (G20) countries and predicted future trends. METHODS: Using data from the Global Burden of Disease 2021 study, the authors examined incidence, mortality, mortality-to-incidence ratio (MIR), age-standardized mortality rate (ASMR), age-standardized incidence rate (ASIR), and average annual percent change. Joinpoint regression was used to identify trend changes. Social demographics index associations were examined. Autoregressive integrated moving average was used to forecast trends to 2040. RESULTS: Between 1990 and 2021, breast cancer incidence in China increased by over 360%, with ASIR rising from 9.42 to 23.65 per 100,000, significantly higher than the G20 average (from 24.85 to 29.45). The most pronounced ASIR increases were observed among men 15-49 years old. Although G20 countries reduced their ASMR from 9.57 to 8.14 per 100,000, China's ASMR increased slightly from 4.71 to 5.04 per 100,000. The MIR declined in both China and G20, especially in females 15-69 years old. Projections suggest continued ASIR growth in China, especially among those 50-69 years old, whereas ASMR is expected to stabilize or decline by 2040. CONCLUSIONS: Breast cancer incidence and mortality are increasing more rapidly in China than in G20 countries, driven by reproductive, lifestyle, and environmental factors. These trends highlight the urgent need for enhanced prevention, targeted screening-particularly for women 50-69 years old-and strengthened international collaboration to mitigate the growing disease burden.