Perspectives in hormone replacement therapy.
Estrogens have been convincingly shown to be highly effective in preventing and reversing menopause-related conditions, such as hot flushes, urogenital complaints, and postmenopausal bone loss. Observational studies report that long-term, estrogen-containing, postmenopausal hormone replacement therapy (HRT) leads to a substantial reduction in hip fractures, myocardial infarction, and possibly colonic cancer, with important consequences for health and quality of life. Estrogen replacement may postpone the onset of Alzheimer's disease and extend life. While many of these effects are biologically plausible, with a variety of cellular mechanisms being involved, only ongoing and future large-scale randomized clinical trials can and should define the effects of HRT more precisely. Long-term compliance is a key issue for long-term benefits, and offering women a choice of administration routes and regimens can only be beneficial in this respect. Pills, patches, gels, and implants are all widely prescribed. Intravaginal or intranasal forms of administration, which are very easy to use and adaptable on an individual level, are among the new options which could improve long-term continuation of HRT use. Fear of breast cancer and recurrence of vaginal bleeding are real concerns for many women considering HRT. This has led to research into lower-dose, estrogen-containing regimens, into continuous combined regimens, and into the potential of estrogen receptor alpha or beta binding molecules that may help to prevent such problems from arising. The prospects for safe and effective postmenopausal HRT with either estrogens or estrogen-like drugs are very promising when these drugs are used in a patient-tailored, risk profile-based manner.