Impact of contraception on gynecologic cancers

In considering the appropriate contraceptive method for a particular woman, the potential effect of that method on her risk of developing cancer of the breast, cervix, endometrium, or ovary is crucial. Among the most closely studied of the risk factors for gynecologic neoplasm has been the potential role of contraceptives, especially oral contraceptives, intrauterine devices, and injectable progestins. Physicians need to consider the potential impact of these agents on the disease process, therapy for the disease, future fertility, and the health of the fetus. Although much of the epidemiologic data is inconsistent and difficult to interpret, most studies find no association between oral contraceptive use and increased risk of breast cancer, except possibly in younger women (< 45 years of age) with prolonged use. Oral contraceptive use may also protect against benign breast disease. Data concerning oral contraceptive use and cervical neoplasm are confounded by several interacting variables, the most important of which is that oral contraceptive users tend to have more Papanicolaou smears than nonusers. Some studies have indicated an increased risk of two- to fourfold after 10 years of use. Oral contraceptive use provides clear protection against endometrial and ovarian cancer, an effect that persists for years after discontinuation. Less data have been collected regarding the relationship between intrauterine devices and injectable hormonal preparations and various types of cancer. No evidence suggests that the intrauterine device predisposes to the development of preneoplastic conditions of the cervix, nor to endometrial or ovarian cancer. A reliable form of contraception is indicated in women with cancer of any kind that may require chemotherapy or radiation, because these treatments can have adverse effects on the fetus, especially if given during the first trimester.