May 6, 2011
Dear Mayo Clinic:
I'm 37 and have the BRCA1 gene mutation. I haven't had children and am not planning to become pregnant any time soon. My doctor has prescribed oral contraceptives, saying it will help protect against ovarian cancer. But I've read that the pill is dangerous for those with a family history of breast cancer. What do you recommend?
Oral contraceptives have been shown to reduce the risk of ovarian cancer in women who carry the BRCA1 and BRCA2 gene mutations. As you note, though, some research has also indicated that oral contraceptives may increase the risk of breast cancer. The general consensus among medical experts who specialize in this area, however, is that the risk reduction for ovarian cancer outweighs any increased risk for breast cancer in BRCA1 and BRCA2 carriers who take oral contraceptives.
In the mid-1990s, researchers discovered that two gene mutations — BRCA1 and BRCA2 — significantly increase a woman's risk of developing breast and ovarian cancer. A variety of methods have been developed to help reduce those risks, including taking medication (chemoprevention), removing healthy breast tissue (prophylactic mastectomy) and removing healthy fallopian tubes and ovaries (prophylactic salpingo-oophorectomy).
Oral contraceptive use has also been associated with a significant decrease in the risk of ovarian cancer for women with a BRCA gene mutation, reducing the risk up to 50 percent. But there have been questions about oral contraceptive use in BRCA carriers because of a possible link between these contraceptives and increased breast cancer risk. However, this association is not completely clear at the present time.
Some studies have suggested that the increased breast cancer risk may be linked to the length of time a woman takes oral contraceptives, with only those who take the pill for more than five years at higher risk. Other research found a correlation between BRCA carriers who had stopped using oral contraceptives 10 years prior to diagnosis and an increased risk of breast cancer. But it's difficult to say if that increase was due to the oral contraceptives, to the time that had passed (because breast cancer risk for BRCA carriers rises over time), or to some other factor that hasn't been considered.
More recent research has indicated that the type of oral contraceptive may make a difference. A 2010 analysis reviewed 2,855 breast cancer cases in women with a BRCA gene mutation. This study found that those who used oral contraceptives before 1975, when doses of hormones in the pill were much higher than they are now, had an increased risk of breast cancer. This same study found no evidence that the women who used more recent formulations of oral contraceptives, with lower doses of hormones, had a higher risk.
With these findings in mind, I recommend that women with a BRCA mutation who still have their ovaries take oral contraceptives, at least for a short time. At your age, you should also begin to seriously consider having your ovaries removed to reduce your cancer risk further. The general recommendation is that women in your situation undergo this surgery once they are finished having their families, or are between the ages of 35 and 40.
With ovary removal, the risk of ovarian cancer in BRCA carriers drops about 95 percent. (It's not 100 percent because there is a small risk that the peritoneum, the tissue which lines the abdominal cavity and has the same embryonic origin as the ovaries, remains after surgery and may develop a similar malignancy.) Also, removing the ovaries decreases breast cancer risk by about 50 percent.
Considering all the issues related to a BRCA gene mutation is a complicated task. If you haven't already done so, I suggest you seek out an OB/GYN physician — or possibly a gynecologic oncologist or a medical geneticist — who is familiar with this topic. He or she can help you sort through the research and information, as well as set up a regular cancer screening schedule, in a way that addresses your concerns and meets your needs.
— Myra Wick, M.D., Ph.D., Obstetrics and Gynecology, Mayo Clinic, Rochester, Minn.