Summary: GAO discussed progress in breast cancer prevention and treatment, focusing on: (1) changes in medical interventions; (2) requirements to improve survival rates; (3) research needed to help prevent breast cancer; and (4) the National Institutes of Health's (NIH) financial support for research of breast cancer compared with other support for research of other conditions. GAO noted that: (1) there has been no progress in preventing breast cancer; (2) changes in medical intervention have led to a stabilization of breast cancer mortality rates; (3) mammography offers the only evidence of improving survival rates; (4) efforts to prevent breast cancer have little chance of success until factors that cause the disease are understood; (5) NIH research expenditures for breast cancer are equivalent or greater to other research for serious conditions, with the exception of acquired immune deficiency syndrome; and (6) earlier detection and more appropriate surgery have increased the likelihood and quality of survival.