Breast cancer risk: perception versus reality.

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.