In the last two decades, there has been a major increase in the actual numbers of women diagnosed with breast cancer (from 65000 new cases 20 years ago in the United States to 183000 in 1993). Concomitant with this has been a shift toward making the diagnosis earlier and toward diagnosing an earlier stage ofthe disease (more than 70% of diagnoses were of advanced-stage disease two decades ago, whereas more than 70% of diagnoses are now earlier-stage disease in 1992). These changes are clearly related to the woman's greater sensitivity to abnormalities in the breast and her seeking medical...