GUEST EDITORIAL Hormonal Contraception and Breast Cancer: Keeping Perspective

In October 2006, a meta-analysis was published in theMayo Clinic Proceedings on the effects of combined oral contraceptive (COC) use on premenopausal breast cancer.1 Unlike previous attempts to examine the effects of oral con-traceptives (OCs) on breast cancer, this study included only reports in which cases and controls were under 50 years of age and the diagnosis of breast cancer was made after 1980. This methodological approach was intended to give a better snapshot of the effect of modern OC usage on breast can-cer in the premenopausal age group. Among 60 potential publications that were identified, 39 met these inclusion cri-teria. Not all of these studies could be included in all parts of the analysis because some were missing important informa-tion that was necessary for stratification of subjects. Standard meta-analytic techniques were employed with independent extraction of data by two reviewers. In addi