Oral Contraceptives May Reduce Risk of Ovarian Cancer in BRCA Carriers

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BRCA mutation carriers who used oral contraceptives for a long period of time had a lower risk of developing ovarian cancer, according to new research.

Long-term use of oral contraceptives was associated with lowered risk of ovarian cancer in BRCA mutation carriers. Though the association between oral contraceptive use and reduced ovarian cancer risk was established for the general population, the risk reduction for BRCA1 and BRCA2 carriers was not as well-understood.

“Only a few studies on oral contraceptive use have examined the associations of duration of use, time since last use, starting age and calendar year of start with risk of ovarian cancer,” the authors wrote in the study, which was published in the American Journal of Obstetrics & Gynecology.

Adding to the wealth of knowledge on BRCA mutation carriers and cancer risks, the research emphasizes the importance of genetic testing, especially in patients who have a family history of ovarian cancer. Genetic testing and knowledge of BRCA status can affect treatment decisions and determine whether an individual is at risk for additional cancers. It can also alert family members of the BRCA carrier who do not have cancer as to whether they are at increased risk for the disease.

“For BRCA1 and BRCA2 mutation carriers it is very important to be aware of the mutation, because the breast cancer risk rises already at very young ages and the risk of ovarian cancer (for which no effective screening exists) is also very high,” said corresponding author Matti Rookus, who holds a post doctorate, in an interview with CURE®. “As a result the impact of the use of oral contraceptives is different for mutation carriers than for other women.”

READ MORE: Study Asks: Are Women Missing Out on BRCA Testing?

To examine whether oral contraceptives reduced cancer risk in BRCA mutation carriers, the researchers assessed data of 3,989 BRCA1 and 2,445 BRCA2 mutation carriers. They found that patients who were mutation carriers who had been diagnosed with ovarian cancer had used oral contraceptives less often than carriers without a diagnosis (58.6% vs. 88.9% for BRCA1 and 53.5% vs. 80.7% for BRCA1).

The median duration of use for both BRCA1 and 2 carriers who developed ovarian cancer was seven years as opposed to nine and eight, respectively, for unaffected carriers. Additionally, analyses showed that a longer duration of use and more recent use were associated with a greater reduction in ovarian cancer risk.

Age at first use and time since last use was a prominent protective factor. The inverse association between duration of use and cancer risk lasted more than 15 years, which demonstrates long term protection.

“Although oral contraceptive use might be considered a preventive approach for developing ovarian cancer, its use in BRCA1 and BRCA2 mutation carriers needs to be weighed against the possible association of oral contraceptive use with increased risk of breast cancer,” the authors wrote.

“To support this judgement, we are currently conducting a study in which we compare the increased and decreased absolute risks,” said Rookus.

However, they added that the association of reduced risk of ovarian cancer is stronger than the possible association of increased risk of breast cancer.

“Further research on the absolute effects of the associations of oral contraceptive use with breast and ovarian cancer weighted with the current practice of risk-reducing surgery is needed,” the authors wrote.

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