Breast cancer incidence in Asian migrants to the United States and their descendants.

We studied breast cancer incidence during the period 1973-1986 in Asian residents of three U.S. geographic areas. The rate in Asian-American women born in China or Japan and in their U.S.-born counterparts was about 50% and 75% that of U.S.-born whites, respectively, and was approximately twice the rate of women residing in Asia. Breast cancer incidence was nearly identical in U.S.- and foreign-born Filipino-Americans, but it was 40% that of U.S.-born whites.