In the original study, 16,608 postmenopausal women were randomized between placebo and a commonly used hormone combination of estrogen and progestin, with Dr. Schenken leading the San Antonio team, a major site for the study.
The initial results, published in 2003, showed taking combination therapy -- estrogen and progestin -- for a long period of time increased the risk of getting breast cancer by 25 percent. Most women stopped taking the combined hormone replacement therapy and some 17,000 fewer women per year got breast cancer, Schenken says.
The long-term follow-up of this initial study shows women who were taking combined hormone therapy not only had an increased risk of developing breast cancer, but developed deadlier forms of breast cancer -- doubling their risk of dying from breast cancer.
The findings are published in the Journal of the American Medical Association.