Contrary to popular belief, the use of oral contraceptives does not reduce the risk of ovarian cancer among women who carry the BRCA1 or BRCA2 mutation, according to a study recently published in the New England
Journal of Medicine.
Ovarian cancer is a common malignancy, with about 25,000 new cases diagnosed in the United States each year. Ovarian cancer has been called the “silent killer” because it begins deep in the pelvis and often does not cause any symptoms until it has reached advanced stages. As a result, ovarian cancer is often initially diagnosed when it has already reached a stage where it is incurable.
The best “treatment” strategy for cancer is to prevent its occurrence or to detect it early when it is most treatable. Ovarian cancer has the highest mortality rate of all gynecologic cancers, which has prompted a great deal of research to identify the causes and risk factors for this disease, with the hopes of creating better prevention strategies. Historically, research has indicated that the use of oral contraceptives, as well as having one or more children, reduces the risk of ovarian cancer; however, researchers have questioned whether these factors reduce the risk of ovarian cancer among women who carry the BRCA1 and BRCA2 mutations.
The breast cancer susceptibility genes, BRCA1 and BRCA2, are also associated with an increased risk of ovarian cancer. These mutations are common among Jewish women. Recently, researchers conducted a population-based, case-control study of ovarian cancer among Jewish women in Israel. The study involved 840 women with ovarian cancer and 751 controls. The researchers tested all subjects for BRCA1 and BRCA2 mutations and then estimated the effects of parity (having had children) and oral contraceptive use on the risk of ovarian cancer in carriers and noncarriers of the mutations.
The results indicated that 1.7% of controls and 29% of women with ovarian cancer had a BRCA1 or BRCA2 mutation. The researchers found that each birth reduced the risk of ovarian cancer for both carriers and noncarriers of the mutations; however, each year of oral contraceptive use reduced the risk of ovarian cancer only for noncarriers of the mutations.
The researchers concluded that the risk of ovarian cancer among carriers of a BRCA1 or BRCA2 mutations decreases with each birth, but not with increased duration of use of oral contraceptives. They caution that it is premature for BRCA1 or BRCA2 carriers to use oral contraceptives for the chemoprevention of ovarian cancer, especially since some research indicates that oral contraceptive use could increase the risk of breast cancer among this group of women.
(New England Journal of Medicine, Vol 345, No. 4, pp. 235-240, 2001)