Evidence that breast cancer is hormonally mediated has fueled women's concern that use of oral contraceptives (OC) will increase their risk of developing the disease. A recent reanalysis of combined worldwide epidemiologic evidence regarding the relationship between breast cancer risk and use of combination OC provides reassurance that there is little or no association between OC use and breast cancer. Ten or more years after discontinuation of OC use, there is no difference in cumulative risk of breast cancer among OC ever-users and never-users. The risk of breast cancer diagnosis is slightly elevated in current OC users and remains slightly elevated until about 10 years after OC discontinuation. Once recency of use is taken into account, other characteristics have little additional effect. There is no increase in breast cancer risk with increasing dose or duration of OC use and no difference in risk related to type of estrogen or progestin used. Moreover, those breast cancers diagnosed in OC ever-users were found to be significantly more likely to be localized than those diagnosed in same-age never-users.
PIP: A recent survey of US women 40-50 years old with no history of breast cancer found that women's perceptions of their risk of developing and dying of breast cancer exceeded the actual risk. Evidence that breast cancer is hormonally mediated has raised concerns that oral contraceptive (OC) use increases a woman's risk of developing the disease. This concern has been fueled by the observation that the increasing diagnosis of breast cancer in many countries has occurred in tandem with widespread OC use. However, a reanalysis by the UK Imperial Cancer Research Fund Epidemiology Unit of worldwide epidemiologic data revealed little or no evidence of a link between OC use and breast cancer. 10 or more years after discontinuation of OCs, there is no difference in cumulative breast cancer risk between OC ever-users and nonusers. Breast cancer risk among ever-users was not affected by duration of OC use, age at first use, parity, family history, or the dose or type of OC. Moreover, breast cancers diagnosed in OC ever-users are significantly less advanced and more likely to be localized to the breast than those in never-users. It may be that current or recent OC users are receiving more breast examinations and therefore have the opportunity for early diagnosis and improved prognosis.