The effects of oral contraceptives on breast and ovarian risks are similar for women with BRCA1 or BRCA2 mutations and for women in the general population, according to analyses of observational studies. Oral contraceptive use “is inversely associated with ovarian cancer risk, whereas a modest but not statistically significant increased risk was observed for breast cancer,” Patricia G. Moorman, PhD, of Duke University School of Medicine in Durham, North Carolina, and colleagues reported in the Journal of Clinical Oncology.
“For BRCA1/2 mutation carriers combined, meta-analysis showed an inverse association between [oral contraceptive] use and ovarian cancer [odds ratio (OR) = 0.58, 95% CI = 0.46 to 0.73],” the investigators found. “The inverse association for ever use of [oral contraceptives] and ovarian cancer for the combined group of BRCA1/2 mutation carriers [OR = 0.58] was stronger than what we observed in our meta-analysis in the general population [OR = 0.73] and what has been reported in an earlier pooled analysis,” the authors noted. “Analyses restricted to BRCA1 and BRCA2 carriers found similar [odds ratios] for [oral contraceptive] use within each gene group, and a test for differences between groups was not statistically significant.”
While oral contraceptive use has been discussed as a potential means of reducing risk of ovarian cancer, the chemoprevention effect of oral contraceptives must be weighed against the possible increased risk of breast cancer, the authors noted. “Our meta-analysis did not suggest a significantly increased risk for breast cancer among BRCA1 or BRCA2 mutation carriers; however, the point estimate among BRCA1/2 carriers [OR = 1.21] was slightly higher than that reported in the general population [OR = 1.08],” the researchers reported.
Differences among studies examining risk for women with a family history of ovarian or breast cancer “precluded combining the data for meta-analyses, and no overall pattern could be discerned,” the investigators added.
“Because of limitations in the data, as well as the need to consider other potential benefits and harms from [oral contraceptive] use, there is insufficient evidence to recommend [oral contraceptive] use as a chemoprevention strategy in high-risk women if they otherwise would not be taking them for contraception. Conversely, if women with BRCA1/2 mutations or family history of breast or ovarian cancer desire to use [oral contraceptives] for contraception, there is no evidence to recommend against their use in these high-risk populations,” the authors concluded. ■