More evidence shows that taking hormone therapy could increase ones risk for breast cancer. A recent study shows postmenopausal women who took estrogen-plus-progestin hormone therapy for one year experienced a two-fold increase in breast density -- a risk factor for cancer. The women's risk of having an abnormal mammogram was four-times greater, as well.
Researchers studied 413 postmenopausal women between ages 50 and 79. The average woman was 62 years old and 12-years post-menopausal. Half of the women received estrogen plus progestin, and the other half received a placebo. All had a baseline mammogram at the beginning of the study and a follow-up mammogram one or two years later.
The effect of hormone replacement therapy was especially high in the oldest age bracket. Women between ages 70 and 79 experienced a nearly three-fold increase in breast density compared to younger women, presumably because their breast tissue was less dense to begin with.
Researchers say these findings are unique in showing a sustained effect over two years and that even in older postmenopausal women, breast density can increase in response to estrogen-plus-progestin therapy. Breast density was measured with a computer-aided technique that calculated the amount of dense, or white-appearing, tissue on digitized mammography images. Denser breast tissue increases a woman's risk for cancer, but makes the cancer more difficult to diagnose because both dense tissue and cancer appear white on a mammography.
In conclusion researchers say their results suggest that avoiding such hormone therapy may help improve the sensitivity of mammograms for detecting early breast cancers at a stage when they are most treatable.