Lieske H. Schrijver, from the Netherlands Cancer Institute in Amsterdam, and colleagues examined the correlation of various characteristics of oral contraceptive use and the risk for ovarian cancer among 3,989 BRCA1 and 2,445 BRCA2 mutation carriers.
The researchers found that mutation carriers who were diagnosed with ovarian cancer had less frequent use of oral contraceptives (ever use: 58.6 percent for BRCA1 and 53.5 percent for BRCA2) compared with unaffected carriers (88.9 and 80.7 percent, respectively). BRCA1 and BRCA2 carriers who developed ovarian cancer had a median duration of oral contraceptive use of seven years compared with nine and eight years, respectively, in unaffected carriers. In univariate analyses, a longer duration of oral contraceptive use and more recent use were both associated with a reduction in the risk for ovarian cancer for BRCA1 carriers. In multivariate analyses, duration of oral contraceptive use was the prominent protective factor (hazard ratios, 0.67 and 0.37 for five to nine years and ≥10 years, respectively, compared with <5 years). The inverse correlation persisted for more than 15 years. Similar results were seen in univariate analyses for BRCA2 mutation carriers.
“We found a clear inverse association between oral contraceptive use and ovarian cancer risk,” the authors write.