Oestrogens and endometrial cancer: effect of other risk factors on the association.

We analyzed data from a case-control study of endometrial cancer to determine whether, in a woman's menstrual and medical history, factors could be identified that modify the increased risk resulting from menopausal oestrogen use. Overweight, hypertension, low parity, non-smoking, late age at menopause, and a history of cholecystectomy were all associated with endometrial cancer, but oestrogen use produced large increases in risk both in the presence and absence of these characteristics. We conclude that information on other known risk factors for endometrial cancer provides little or no guidance as to which patients to select in the perimenopause.