Recent incidence trends for breast cancer in women and the relevance of early detection: an update.

The incidence of breast cancer in women has been rising dramatically in the United States since 1982, based on data collected by the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute. An additional three years of incidence and mortality data are included in this update of the earlier analyses; however, the focus of this report remains on examining the steeply increasing incidence trend between 1982 and 1986. Over this period, incidence rates for in situ and localized invasive tumors increased among women age 50 and older, while rates for regional and distant tumors remained stable. The incidence of localized tumors less than 1.0, 1.0 to 1.9, and 2.0 to 2.9 cm in size increased more rapidly than that of tumors 3.0 cm and greater among women over age 50. Survival rates also improved among cases diagnosed over this time period. These descriptive data suggest that early detection may be playing a role in the recent increase in the incidence of breast cancer in women, although other factors cannot be ruled out. Conclusions regarding improved cancer control await confirmation by reduced breast cancer mortality.