Abstract

PIP: The exemplary study of Weiss and Sayvetz of the risk of endometrial cancer among oral contraceptive (OC) users is reported. The only study limitation is that the cases available were too few to provide highly precise estimates of all the associations seen. Yet the study did show that women who took the sequential drug Oracon have a risk of endometrial cancer that is appreciably higher than that of women who did not take OCs. The study also provides some evidence that the combined drugs do not increase the risk of endometrial cancer and that they might actually be protective. The study can only suggest that other sequential drugs are not as harmful as Oracon and that they may even be protective like the combined drugs. Oracon differed from all other OCs in 3 ways, and each contributed to making it the most estrogenic: 1) only Oracon used the weak progestogen dimethisterone; 2) only Oracon supplied 100 mg daily of the estrogen ethinyl estradiol; and 3) Oracon's monthly sequence included 16 days of estrogen alone while other sequential drugs included 14 or 15 days, and the combined OCs have no estrogen-only day. The finding of Weiss and Sayvets that, if accurate, will prove to be of greatest importance is the apparent anticarcinogenic effect of combined oral contraceptives.