Oral Contraceptives Linked to Reduced Risk of Ovarian Cancer and Nonsignificantly Increased Breast Cancer Risk in Women With BRCA1/2 Mutation
In a study reported in the Journal of Clinical Oncology, Patricia G. Moorman, PhD, of Duke University Medical Center, and colleagues evaluated risk of ovarian and breast cancer among oral contraceptive users with BRCA1/2 mutations. The study showed a significantly reduced risk of ovarian cancer and a nonsignificantly increased risk of breast cancer among "ever users" of oral contraceptives, similar to risks observed in the general population.
Study Details
The study consisted of meta-analyses using data from four studies examining ovarian cancer risk and five studies examining breast cancer risk in BRCA1/2 mutation carriers published between 2000 and 2012 and identified in searches of PubMed, Embase, the Cochrane Database of Systematic Reviews, and ClinicalTrials.gov. The four studies examining ovarian cancer risk included a cohort study representing 3,181 subjects and three case-control studies representing 1,096 cases and 2,878 controls. The five studies examining breast cancer risk included three case-control and two cohort studies representing 4,555 subjects (four studies) and 65,180 person-years (one study).
Ovarian Cancer Risk
Summary odds ratios for ovarian cancer for ever vs never oral contraceptive users were 0.55 (95% confidence interval [CI] = 0.47–0.66) among BRCA1 mutation carriers, 0.65 (95% CI = 0.34–1.24) among BRCA2 mutation carriers, and 0.58 (95% CI = 0.46–0.73) for carriers of either mutation.
Breast Cancer Risk
Odds ratios for breast cancer for ever vs never oral contraceptive users were 1.19 (95% CI = 0.92–1.55) among BRCA1 mutation carriers, 1.36 (95% CI = 0.89–2.10) among BRCA2 mutation carriers, and 1.21 (95% CI = 0.93–1.58) among those carrying either mutation.
Data were insufficient to permit meta-analyses examining effects of duration or timing of oral contraceptive use or to permit meta-analyses of the effects of oral contraceptive use according to presence or absence of family history of ovarian or breast cancer.
As noted by the investigators, ever use of oral contraceptives is associated with an approximately 30% reduction in incidence of ovarian cancer and a small increase in risk of breast cancer (odds ratio = 1.08) in the general population, with a greater risk of breast cancer being observed in current or recent users.
The investigators concluded, “Our analyses suggest that associations between ever use of [oral contraceptives] and ovarian and breast cancer among women who are BRCA1 or BRCA2 mutation carriers are similar to those reported for the general population.”
The study was supported by contracts with the Agency for Healthcare Research and Quality and the Centers for Disease Control and Prevention.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
