Postmenopausal estrogens and progestogens and the incidence of gynecologic cancer.

We reviewed the published medical literature to assess the impact of the use of estrogens, with and without progestogens, on the incidence of gynecologic cancer in postmenopausal women. Long-term use of an estrogen preparation that is not accompanied by a progestogen is associated with a large increase in the risk of endometrial cancer, an association that almost certainly is a causal one. The incidence of endometrial cancer in women who receive combined estrogen-progestogen therapy is not elevated to nearly the same degree. There are suggestions that, depending on the particular combined regimen, the incidence need not be elevated at all beyond that of a women who has never taken hormones. The occurrence of other forms of gynecologic cancer appear not to be associated with the use of unopposed estrogens, though relevant data on cervical cancer are sparse. The relation of ovarian, cervical and vulvar cancer to the prior use of combined estrogen-progestogen therapy has only begun to be evaluated.