BREAST CANCER RATES FALL BREAST CANCER RATES FALL U.S. breast cancer rates drop dramatically Breast cancer rates fell 7% in 2003, the year after millions of older women abandoned hormone-replacement therapy based on the findings of a government report. Scientists don't know if that drop will continue in the future, and some experts question whether such a big change could be caused by a single factor. The report, led by researchers at Houston's M.D. Anderson Cancer Center, states it's significant that breast cancer rates dropped the most — 12% — among women 50 to 69, whose tumors feed on estrogen. That's the age range most likely to have used hormone therapy to relieve menopausal symptoms, says senior study investigator Donald Berry of the cancer center. ON DEADLINE: Read the study's findings Berry says it makes sense that stopping hormone therapy would slow the growth of tumors fueled by estrogen. About 30% of women older than 50 took hormone therapy in the early years of this decade, according to the report. About half of them stopped taking the pills after the release of findings of the Women's Health Initiative in July 2002, when researchers announced that hormone therapy can increase the risk of both heart disease and breast cancer. With more than 200,000 cases of breast cancer diagnosed each year, the rate drop suggests that about 14,000 fewer women were diagnosed with the disease in 2003, according to the study. The sharp drop is all the more striking, Berry says, because the breast cancer rate had actually grown 30% from 1975 to 2000. That figure factors in the increase in mammography, which tends to increase the number of tumors diagnosed. Other doctors say there are sound scientific reasons why the breast cancer rate could change so suddenly. Some early tumors are just on the verge of being big enough to be spotted on mammograms, says Eric Winer, director of breast oncology at Boston's Dana-Farber Cancer Institute. These tumors, when deprived of hormones, may stop growing, so they don't show up in the breast screenings, he says. Some of those tumors may grow more slowly, leading them to be detected later. Others may shrink or even disappear. These women may never be diagnosed with breast cancer, Winer says. Experts around the nation are already looking into the change, says Ahmedin Jemal of the American Cancer Society. "It could be a trend," Jemal says. "But it's one year's worth of data, so it's difficult to say." Doctors will watch over the next few years to see if the drop continues, says Julia Smith of the New York University Cancer Institute. Smith says it's hard to believe that the change could be due to a single factor. But, she adds, "It's good news, any way you look at it."