[Oral contraception and the risk of breast cancer. Review of the literature].

At present an estimated hundred millions of women worldwide use oral contraception, but the influence of hormonal contraception on carcinogenesis of breast is not fully understood. Previous studies of breast cancer risk show inconsistent findings - from zero elevation to approximately 30%-40% increase in risk. The beneficial effect on ovarian and endometrial cancer risk is apparent. In this literature review we attempt to determine effects of oral contraception in relation to the risk of breast cancer. The risk increased with longer duration of use, but absolute increase is very small. "Beneficial effects of OCs on the gynecological cancers thus outweighed adverse effects." (Vessey).