New England Journal of Medicine 294(23): 1262-1267, 1976.
Mack TM, Pike MC, Henderson BE, et al.
To try to confirm reports that conjugated-estrogen use is causally linked with endometrial carcinoma, various measures of drug use and the invasiveness of endometrial cancer were studied in cases and controls chosen from an entire population in an affluent retirement community. The risk ratio for any estrogen use was estimated from all available evidence to be 8.0 (95% confidence interval, 3.5 to 18.1), and that for conjugated estrogen use to be 5.6 (95% confidence interval, 2.8 to 11.1). Increased risk from estrogens was shown for invasive as well as noninvasive cancer, and a dose-response effect was demonstrated. For an estrogen user, the risk from endometrial cancer appeared to exceed by far the baseline risk from any other single cancer. Although no estrogens are completely safe, it is recommended that, where indicated, they be administered cyclically and in the smallest possible dose. Because of a latency of up to 8 yr and because of a recent upsurge in prescriptions, the increase in endometrial cancer can be expected to continue past 1980.
Rheinische Friedrich- Wilhelms- Universität Bonn