Approximately twelve percent of the women in the United States will develop breast cancer, the most common form of cancer affecting women, with 183,000 new cases projected for 1995. Despite the increasing incidence, the age-adjusted death rate from carcinoma has remained relatively stable. Although the reason for this has not yet been demonstrated, this stability may be a direct consequence of early detection and improved therapy. Screening mammography as an early detection technique has been shown to reduce mortality by 23%. Mammographic abnormalities that go on to biopsy show 24% being positive for malignancy with great variability (6-75%). Breast biopsy is an expensive procedure with the risks of anesthesia and surgery which may be obviated by more specific non-invasive testing.