Declining breast cancer mortality among young American women.

Changes in age-specific breast cancer mortality rates among white females in the United States during 1950-80 were shown to be correlated with changes in patterns of childbearing in early adulthood. However, for the most recent 5-year period among women below age 40 years, small declines in breast cancer mortality were observed in the late 1970's, despite a predicted increase following delays in childbearing that began in the 1960's and despite evidence of a rising incidence of the cancer. Although correlation analyses have inherent limitations, the findings raise the possibility that recent changes in the detection and management of breast cancer have contributed to a lowered mortality from this cancer among young American women.