Study Linked Hormone Replacement Drugs To Breast Cancer. Breast cancer rates in the United States dropped 7.2 %, dramatically reversing previous trends which consistently showed rising rates. While the turnaround is surprising news to most, it does not surprise critics of hormone replacement drugs. In 2003, a large federal study linked HRT drugs like Prempro and Premarin, to an increased risk of breast cancer. Within months, millions of women stopped taking estrogen and progestin pills.
Withdrawing Hormones Caused Small Tumors
Medical researchers has exected about 200,000 cases of breast cancer in 2003; but only 14,000 were actually diagnosed with the disease. Because breast cancer takes years to form, experts think that withdrawing hormones mostly caused small tumors that had been growing to stop or shrink, making them no longer detectable on mammograms. Whether this is true or will result in fewer cases over the long run will take more time to tell.
Cases declined most among women 50 and older, with tumors whose growth is fueled by estrogen the age group and type of cancer most affected by hormone use. Researchers looked for a similar drop in other cancers, which could indicate something other than hormones was at work, “and we didn’t see anything,” said Kathy Cronin, a National Cancer Institute statistician who worked on the analysis.
Doctors estimate that half of women who were taking hormones stopped after July 2002, when the federal Women’s Health Initiative study was halted because more women taking estrogen/progestin pills developed breast cancer or heart problems.