Breast cancer cases among women in the US unexpectedly declined by seven percent (14,000 cases) in 2003, one year after millions of women stopped taking estrogen-progestin hormones for menopause, new research shows. No link between hormone therapy and breast cancer has been proven, and while a research analysis released at the San Antonio Breast Cancer Symposium last Thursday suggested a possible cause-and-effect relationship, the correlation is inconclusive.
The most significant decreases in cancer rates occurred among cases of women age 50 and older, and the type of tumors that decreased the most were those “fueled by estrogen,” both of which suggest a link between cancer and the hormone use, the AP reports. Since findings in 2003 showed that hormone use correlated with breast cancer and heart problems, the number of women taking estrogen-progestin pills has dropped by half.
Scientists, however, are urging a more nuanced approach to the correlation. Peter Ravdin, a research professor in the Department of Biostatistics at M.D. Anderson Cancer Center, mentioned that other factors, such as the use of anti-estrogen drugs, cholesterol-reducing drugs, and a drop in mammography rates, may have contributed to the decrease in reported cases of breast cancer, Kaiser Daily Women’s Health Policy reports.