Hormone replacement therapy (HRT)— risks and benefits

Despite 50 years of use, the first large randomized placebocontrolled clinical trials of postmenopausal hormone treatment and disease have only been reported in the last few years. These trials provided some surprising results, and raise questions about the short-term risk and long-term benefit of estrogen. Because clinical trials are the cornerstone of evidence-based medicine, this paper emphasizes clinical trial results whenever such are available. Clinical trials have shown that estrogen therapy is very effective treatment for vasomotor symptoms (hot flushes and night sweats), 1 which can begin several years before the last menstrual period when hormone levels are fluctuating. 2 Clinical trials have also shown that estrogen can reduce vaginal dryness and urethritis, and that topical estrogen is at least as effective as systemic estrogen. 3 The big questions about hormone therapy are not about short-term use for vasomotor symptoms or topical use for urogenital symptoms, but about long-term systemic use with its possible benefits, such as prevention of fractures, heart disease, colon cancer, or dementia, and risks, most notably breast and uterine cancer. 4