Hormone therapy mainly consisted of Estrogen-only or estrogen plus progestin. It was mainly prescribed for women treat menopausal symptoms. It was originally prescribed to quell hot flashes and other symptoms of menopause, but there were also indications that the therapy lowered the risks of heart disease, bone loss and possibly other ailments. Hormone replacement therapy came under scrutiny when research called the Women's Health Initiative study was terminated early, in February 2004, because of unexpected findings that women faced heightened risks of ailments including stroke, blood clots and breast cancer. Since then, further analysis of the WHI study data and other studies has generated confusion.
But a recent study said that hormone replacement therapy used to treat symptoms of menopause does not raise the risk of breast cancer for women who have had a hysterectomy. The finding contrasts with the higher risk of breast cancer among menopausal women taking estrogen plus progestin which is a combination designed to protect against uterine cancer. In hysterectomy all or part of the uterus is removed. Dr. Elizabeth Nabel, director of the National Heart, Lung, and Blood Institute of the National Institutes of Health, which sponsored the WHI study said that hormone therapy should only be used to treat menopausal symptoms and should be used at the smallest effective dose for the shortest possible time. After the WHI study was published, sales of Wyeth's leading hormone replacement drugs Premarin and Prempro fell dramatically.
A new study done by Marcia Stefanik of Stanford University was published in the Journal of the American Medical Association, covered nearly 11,000 women participating in the WHI study who had a hysterectomy. It was found that there were fewer breast cancers diagnosed for women on the active study pills when compared to those taking harmless sugar pills. But the tumors were significantly larger and had a tendency to spread to more lymph nodes. The women taking estrogen had slightly fewer breast cancers but they had more follow-up mammograms and biopsies performed. The hormone tends to make breast tissue denser and therefore more difficult to detect tumors. Hence there still exists some sort of confusion over the effectiveness and safety of the therapy.