Estrogen Drugs: Do They Increase the Risk of Cancer?

Several reports and investigations have suggested that an association exists between estrogen drug use and increased risks of cancer. The incidence of cancer of the endometrium has risen in the past few years following rapid expansion of estrogen use. It has been found that the association between estrogens and endometrial cancer applies to women taking conjugated estrogens for menopausal symptoms as well as the nonsteroidal estrogen diethylstilbestrol (DES). The increase in endometrial cancer was most marked in Caucasian women in high socioeconomic groups who are 50 years of age or older. Studies have indicated that estrogens especially when unopposed by progesterone may play a causal role in the development of endometrial cancer. There are preliminary indications that the sequential type of oral contraceptive (OC) may be associated with endometrial cancer. Other investigations have found that use of OCs has increased the risk of breast cancer in women already predisposed to it. Definite answers to the questions about OCs and cancer will take time.