Breast cancer among Asian Americans

Abstract

Breast cancer is the most commonly diagnosed cancer in women. Studies of breast cancer incidence have shown consistently two to threefold higher incidence rates among Asian-American women living in the United States (USA) relative to Asian women living in Asia. For example, breast cancer incidence in Japanese Americans is now approaching rates in Non-Hispanic (NH) Whites after two or three generations living in the USA. Epidemiologic data from studies conducted in Asian Americans, NH Whites, and in Asia reviewed in this chapter show that differences between incidence rates in NH Whites and US-born Asians are explained, in part, by menstrual and reproductive factors, body size, and use of hormonal replacement therapy. Changing prevalence of risk factors likely have had a major role in explaining the rise in breast cancer incidence with migration while the magnitude of risk associations for most of the risk factors are comparable to those of NH Whites. We review etiological risk factors that may explain the continued differences in rates between Asian Americans, Asians, and NH White women.