Exogenous estrogens and endometrial cancer

Abstract

Reports in the lay press that exogenous estrogens cause endometrial cancer are unjustified with the present evidence. The epidemiologic method used to identify retrospectively an increased association of estrogens with endometrial cancer cannot prove causality. Mortality from endometrial carcinoma has not increased in this country and may actually be starting to decline.

PIP: Reports in the lay press that exogenous estrogens cause endometrial cancer are unjustified with the present evidence. Mortality from endometrial cancer has not increased in the U.S. in recent years. Endometrial cancer accounts for only 1.38% of all female cancer deaths. The incidence in the U.S. has not increased since estrogen therapy has been more widely used. The acquisition of an unbiased control group is the prime requirement if valid conclusions are to be made. 1 of the most difficult problems in a retrospective study of endometrial cancer is identification of a group of women who have undergone diagnostic uterine curettage or biopsy or hysterectomy. Exclusion from the comparison group of women who have had a hysterectomy excludes a large number who would have had an opportunity for estrogen replacement therapy following the menopause. An association between 2 factors does not prove cause. It is to be hoped that fear of endometrial cancer from exogenous estrogen therapy will turn out to be a false alarm when better retrospective studies are reported or when material from the studies reported to date is reviewed further. Meantime caution is indicated. Cyclic administration of estrogens in small doses for the shortest practical time is advised. Periodic examinations, Papanicolaou smears, and frequent evaluation of the patient's symptoms are recommended. There are definite and established benefits of estrogen therapy as well as risks.