OCs and Ovarian Cancer Risk with BRCA Mutations

Only 10% of ovarian cancer is hereditary, but many studies have examined women in this subgroup. Unselected long-term OC users have a 50% reduced ovarian cancer risk. This study evaluated OC use in 207 BRCA1- or BRCA2-positive women (mean age, 54) with ovarian cancer. Controls were 161 sisters of case women without ovarian cancer; 53 carried the mutation.

In multivariate analysis, the odds ratio for ovarian cancer with OC use was 0.5 (95% CI, 0.3 to 0.8). Among control women with mutations, the OR was 0.4 (CI, 0.2 to 0.7). Ovarian cancer risk decreased with duration of OC use, with the greatest reduction in women who used OCs for longer than six years.