Background: Oral contraceptive use is associated with a significantly reduced risk of ovarian cancer among BRCA1 and BRCA2 mutation carriers. To date, there have been no prospective analyses of this relationship, and the impact of other types of contraception (e.g. intrauterine device (IUD), implant, patch, injection) on BRCA-associated ovarian cancer risk is unknown. The goal of this study is to prospectively evaluate the relationship between types of contraception and ovarian cancer incidence in women with a BRCA1 or BRCA2 mutation.

Methods: The longitudinal study included 3,298 eligible BRCA1/2 mutation carriers. Self-reported information regarding contraceptive use, including medication name, start year, end year, duration of use and method of administration were collected by biennial questionnaire. Women were classified according to history of contraceptive use (ever/never), duration of use, contraceptive method, calendar year of initiation and time since last use. Time-dependent Cox proportional hazards regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) of ovarian cancer associated with each contraceptive method.

Results: There were 84 incident ovarian cancer cases diagnosed over a mean follow-up period of 5.1 years. There was no significant association between ever use of an IUD (HR: 0.78; 95% CI: 0.28-2.14) and risk of ovarian cancer compared to IUD never users. Ongoing analyses will focus on the relationships between other contraceptive methods, formulations and duration of use on ovarian cancer risk, further stratified by histology and site of origin.

Conclusions: Preliminary findings from this prospective analysis suggest that IUD use may not be protective among BRCA1/2 mutation carriers. Ongoing results will elucidate the impact of contraceptive formulation and method on ovarian cancer risk to inform clinical recommendations surrounding the use of contraceptive agents for chemoprevention in high risk women.

Citation Format: Yue Yin Xia, Jan Lubinski, Barry Rosen, Pal Moller, Andrea Eisen, Peter Ainsworth, Leigha Senter, Louise Bordeleau, Susan L. Neuhausen, Christian F. Singer, Jennifer Brooks, Ping Sun, Steven A. Narod, Joanne Kotsopoulos. Contraceptive use and ovarian cancer risk in BRCA1 and BRCA2 mutation carriers: A prospective cohort study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 878.