A risk-benefit assessment of estrogen therapy in postmenopausal women.

Estrogen therapy is extremely effective in relieving menopausal symptoms such as hot flushes, night sweats, urogenital atrophy and certain psychological symptoms. The short term side effects from this therapy are usually mild and self-limiting. They are more common in women who commence hormone replacement therapy some years after the menopause than in those who start treatment at about the time of the ovarian failure. Pre-existing gynaecological conditions such as fibroids and endometriosis can be worsened by estrogen therapy. The majority of published studies suggest a beneficial effect of postmenopausal estrogen therapy on cardiovascular and cerebrovascular disease. These effects may be mediated by favourable changes in lipids, but other mechanisms may also be involved. It is uncertain whether the adverse changes in lipids caused by progestogen therapy will reduce any of the benefits of estrogen therapy on the cardiovascular system. Osteoporosis is the major bone disease of the Western world; long term estrogen therapy will prevent its development in most postmenopausal women. The risk of endometrial carcinoma is increased with unopposed estrogen therapy; this increased risk appears to be abolished if a progestogen is added at an adequate dose and duration for each cycle. The risk of ovarian or cervical cancer is not increased with estrogen therapy. There may be an increased risk of breast carcinoma with long term postmenopausal estrogen use, but the studies show inconsistent results.