Cancer of the uterine corpus after hormonal treatment for breast cancer.

Among 45853 women in whom breast cancer was diagnosed after age forty-nine, from the series of the End Results Program of the National Cancer Institute, cancer of the uterine corpus subsequently developed in 203. The risk was greater among those women receiving hormones than in other treatment groups, and tended to rise with increasing interval from first treatment. One method of estimating an expected value indicated that the excess risk of corpus cancer in breast-cancer patients was restricted to those treated with hormones. Given the time period under study, it may be assumed that the hormones were primarily non-steroidal oestrogens.