Finding suggests that drops in HRT use explain the trend, researchers say
FRIDAY, Feb. 19 (HealthDay News) -- Breast cancer rates are declining, especially among women over 50 who have estrogen receptor-positive tumors, and now a new study narrows down the reason why.
After analyzing data on more than 350,000 women with breast cancer, Harvard researchers concluded that the decline may be linked with decreasing use of hormone replacement therapy -- and that association, in turn, may explain why the decline is especially evident among white, affluent women.
Those are the very women most likely to have used hormone replacement therapy, experts said, and to have stopped using it following the July 2002 release of the results of the Women's Health Initiative, a large national study that discovered an increased risk of breast cancer and heart disease with hormone replacement therapy.
The new study lends credence to the speculation about what's behind the decline. "Our study provides evidence to support the idea that the observed declines are due to the changing use of hormone therapy, by showing that the declines in breast cancer rates were sharpest among those women most likely to have received hormone therapy -- that is, affluent white women," said study co-author Jarvis Chen, a research scientist at the Harvard School of Public Health.
The new study was released online Feb. 10 and will be published in the April supplement of the American Journal of Public Health.
"We further showed that declines in breast cancer rates vary within racial/ethnic groups by socioeconomic position, and that the declines primarily affect rates of estrogen receptor-positive cancers," Chen said.
Lead study author Nancy Krieger, a professor in the department of society, human development and health at the Harvard School of Public Health, and her colleagues analyzed breast cancer data from the U.S. Surveilla
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