Risk/benefit considerations of antiestrogen/estrogen therapy in healthy postmenopausal women.

Using data on potential years of life lost to ages 75 and 85, the potential effect of antiestrogens and estrogens on various competing causes of death is explored. Although for antiestrogens the beneficial effect sought is a reduction in breast cancer mortality, this could be largely eliminated by a small detrimental effect on cardiovascular disease mortality. Other competing causes of death, such as endometrial, ovarian, and liver cancer, and fractured neck of femur (as an indicator of osteoporosis), are of far less import. For estrogen use at the time of the menopause, no effect on mortality is sought. However, an adverse effect on breast cancer mortality would be of far greater significance than an effect on endometrial cancer. Indeed, the present endeavor to counter an adverse effect of estrogens on endometrial cancer by adding progestogens could be counterproductive. These competing causes of mortality have to be borne in mind in designing intervention trials.