Severe atypical endometrial changes and sequential contraceptive use.

Of eight young women, seven had a diagnosis of well-differentiated endometrial adenocarcinoma and one had atypical endometrial hyperplasia. The average age was 40.1 years, with 6.04 years of dimethisterone-ethinyl estradiol (Oracon) sequential contraceptive use. The patients were not typical of those in whom endometrial carcinoma develops. Although these cases do not prove that long-term administration of dimethisterone-ethinyl estradiol causes endometrial adenocarcinoma or atypia, they indicate that it may do so.