This year, an estimated 44,300 women will die of the disease nationwide, but that estimate could prove to be too high if the trend continues. In both White and Black women, the greatest improvements in mortality during the recent 5-year period were seen in younger age groups, but the overall changes were more modest among Black women than in White women of all ages. The median age at death for White breast cancer patients is 68 years and 62 years for Black breast cancer patients. Experts believe the recent decline in breast cancer mortality is partly a result of mammography screening, which rapidly increased in the United States during the 1980s and resulted in a shift toward the detection of breast cancer at earlier, more curable stages. But experts say screening cannot explain all of the decline.
Research is now under way to investigate the impact of adjuvant therapy on mortality rates.
Health authorities in the United Kingdom have also reported a steep decline in the breast cancer death rate among women aged 55 to 69 years during roughly the same time period. The mortality rate in this group dropped 12 percent from 1987 to 1994. This trend began at the same time as the introduction of the United Kingdom's breast screening program, but researchers there have concluded that it occurred too soon to be entirely a result of screening. Instead, they attribute much of the decline to more effective treatment, particularly the widespread adoption of tamoxifen therapy. These results add weight to the evidence for a similar beneficial effect of treatment advances on breast cancer mortality in American women.