Hormone Replacement Therapy Raises Breast Density

Hormone Replacement Therapy Raises Breast Density
Tue Sep 20, 7:02 PM ET

TUESDAY, Sept. 20 (HealthDay News) -- The use of estrogen/progestin hormone replacement therapy for up to two years is linked with increased mammographic breast density, which can hinder the sensitivity of mammography screening and increase a woman's breast cancer risk, researchers say.

Reporting in the Sept. 21 issue of the Journal of the National Cancer Institute, investigators at the Fred Hutchinson Cancer Research Center in Seattle analyzed data from 413 women who took part in the Women's Health Initiative, a randomized trial of more than 16,000 women who received either estrogen plus progestin or a placebo for menopausal symptoms.

The Women's Health Initiative found that women who received the hormone therapy were more likely to be diagnosed with breast cancer, and were also more likely to be diagnosed with advanced breast cancer. The study also found that women who had hormone therapy were more likely to have abnormal mammograms than women who took the placebo.

In this new study, researchers found that women who had hormone therapy had a 6 percent increase in mammographic density over the first year, while the women taking the placebo experienced a 1 percent decline in mammographic density. After two years, the changes persisted in both groups, but were somewhat weaker.

The findings appear in the Sept. 21 issue of the Journal of the National Cancer Institute.

In response to the findings, Wyeth Pharmaceuticals issued a prepared statement, saying, "While the study shows an increase in mammographic density in participants on estrogen plus progestin therapy, it is unclear from the study and others whether changes in mammographic density are an actual marker of increased breast cancer risk or simply an interesting biologic effect."

"The information from this most recent publication should be considered as part of the individualized assessment of risk and benefit for women who are taking or considering estrogen and progestin therapies," added Candace Steele, the director of Wyeth global public relations.

More information

Breastcancer.org has more about mammograms.