Breast cancer risk is increasing in most Asian female populations, but little is known about the long-term mortality trend of the disease among these populations. We extracted data for Hong Kong (1979–2005), Japan (1963–2006), Korea (1985–2006), and Singapore (1963–2006) from the World Health Organization (WHO) mortality database and for Taiwan (1964–2007) from the Taiwan cancer registry. The annual age-standardized, truncated (to ≥20 years) breast cancer death rates for 11 age groups were estimated and joinpoint regression was applied to detect significant changes in breast cancer mortality. We also compared age-specific mortality rates for three calendar periods (1975–1984, 1985–1994, and 1995–2006). After 1990, breast cancer mortality tended to decrease slightly in Hong Kong and Singapore except for women aged 70+. In Taiwan and Japan, in contrast, breast cancer death rates increased throughout the entire study period. Before the 1990s, breast cancer death rates were almost the same in Taiwan and Japan; thereafter, up to 1996, they rose more steeply in Taiwan and then they began rising more rapidly in Japan than in Taiwan after 1996. The most rapid increases in breast cancer mortality, and for all age groups, were in Korea. Breast cancer mortality trends are expected to maintain the secular trend for the next decade mainly as the prevalence of risk factors changes and population ages in Japan, Korea, and Taiwan. Early detection and treatment improvement will continue to reduce the mortality rates in Hong Kong and Singapore as observed in Western countries.

(Cancer Sci 2010; 101: 1141–1246)