Breast cancer cases in the U.S. began to fall as a large number of women ceased hormone replacement therapy (HRT), new research reveals.
Findings published in the New England Journal of Medicine suggest that HRT may raise a womans risk of cancer, particularly if she continues treatment for more than two years.
Oncologist Dr. Rowan Chlebowski and colleagues analyzed the trend, following a study that revealed higher rates of both heart disease and breast cancer among women using pills containing estrogen and progestin.
“If you stop hormones, the risk of breast cancer [associated with hormone use] rapidly declines,” Chelebowski told HealthDay News.
The researchers also explored an alternative hypothesis explaining the breast cancer decrease, which was that women were having more mammograms. They did not find the evidence to be statistically significant.
However, not everyone agrees that the link between HRT and breast cancer is sufficient. The International Menopause Society told Reuters that it would take years for breast cancer rates to show a statistical difference, while the researchers suggest the difference was fairly immediate.