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ESTROGEN REPLACEMENT AND BREAST CANCER: A META- ANALYSIS.

Postmenopausal estrogen replacement retards bone loss and probably lowers a woman's risk of coronary artery disease, but some data have raised the question of whether it increases the risk of breast cancer. This meta-analysis, which pooled data from 16 case-control studies of noncontraceptive estrogen use, found that the risk of breast cancer increased significantly with the duration of use.

The risk did not increase until estrogen had been used for at least five years, but after 15 years of estrogen use there was an estimated 30 percent increase in risk. The excess risk was particularly great among women with a family history of breast cancer, in whom estrogen use was associated with a relative risk of 3.4. The increased risk was also high in studies that included premenopausal women, in whom the risk increased to 2.2 after 15 years of estrogen use.

These data strongly suggest that the suspected relation between estrogen and breast cancer is real. Whether this risk outweighs the considerable health benefits of postmenopausal estrogen use, however, is a complex determination that should probably be made by each woman and her physician.

— THL

Published in Journal Watch General Medicine April 19, 1991

Citation(s):

Steinberg KK et al. A meta-analysis of the effect of estrogen replacement therapy on the risk of breast cancer. JAMA 1991 Apr 17 265 1985-1990.

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