A decline in hormone replacement therapy may be causing a decrease in the rates of a known risk factor for breast cancer, according to researchers.
A recent study published in the November issue of Cancer Epidemiology, Biomarkers & Prevention has shown that the rate of a benign breast condition known as atypical ductal hyperplasia has decreased along with the decline in hormone replacement therapy (HRT) seen since 2002. Atypical ductal hyperplasia is a known risk factor for developing breast cancer, and is suspected of being a breast cancer precursor. According to researchers, women diagnosed with atypical ductal hyperplasia have a 3 to 5 times higher rate of developing cancer in either breast.
In this study, researchers compared the atypical ductal hyperplasia rate in 1999 and 2005, and found that it decreased from 5.5 per 10,000 mammograms to 2.4 per 10,000 mammograms. Over the same time period, the rate of mammography increased, and the rate of HRT use decreased from 35 percent to 11 percent.
The debate over a link between the use of combined estrogen and progestin hormone replacement therapy (HRT) for menopause and cancer has been raging ever since the Women’s Health Initiative (WHI) Hormone Program showed an increase in cancer in women taking Prempro in 2002. The study was halted early in July 2002 when the increased breast cancer risk was detected. As a result, there has been a a huge decline in women taking combined estrogen/progestin HRT.
Quite quickly after the drop in HRT use began, researchers also began seeing a drop in breast cancer cases. The decrease in atypical ductal hyperplasia seen in this more recent research may shed light on exactly how HRT causes the development of breast cancer. Of course, the results of this study are not strong enough on their own to prove that a decline in atypical ductal hyperplasia was caused by a decline in HRT, but the correlation is striking.
Along with the release of this research, combined estrogen/progestin HRT took another hit in November when a jury found that Pfizer, manufacturer of the HRT drugs Prempro and Provera, must pay an Illinois woman at least $6.3 million in damages because of their drugs’ connection with her breast cancer. Pfizer recently acquired Wyeth, the maker of Prempro. Wyeth had previously lost 6 of 9 lawsuits related to Prempro and breast cancer.