The Pill and the BRCA Genes

An international team of researchers has concluded that women who carry mutations in the BRCA1 and BRCA2 genes-which significantly increases the risk of developing breast and ovarian cancer-will not reduce their ovarian cancer risk by taking oral contraceptives.

Of the 23,000 cases of ovarian cancer diagnosed annually in the United States, about 5 percent are due to an alteration in the BRCA1 or BRCA2 genes. Approximately 5 - 10 percent of breast cancer cases can be attributed to these genetic mutations.

Previous studies have shown that the use of oral contraceptives (birth control pills) can reduce the risk of ovarian cancer for women in general. However, this new study appears to indicate that this benefit does not convey to women with the BRCA1 and BRCA2 gene alterations.

Writing in the New England Journal of Medicine, researchers from the National Israel Ovarian Cancer Study Group and the National Cancer Institute reported on their study of 840 Israeli women with ovarian cancer and 751 women in a control group.

The researchers found that for women with alterations in BRCA1 or BRCA2 genes, the use of oral contraceptives did not increase or decrease their risk of ovarian cancer. However, they did observe that for women without these genetic alterations, the use of contraceptives did indeed lower their ovarian cancer risk. Therefore, the study supports previous reports that the use of oral contraceptives will reduce the risk of ovarian cancer in the vast majority of women.

The researchers cautioned that a definite conclusion regarding oral contraceptive use and women with alterations in BRCA1 or BRCA2 genes is still premature. Additional research is needed to confirm or refute these findings, they said.

The study did not directly address the risk of breast cancer in terms of oral contraceptive use. However, previous studies have shown that oral contraceptives do not affect the risk of breast cancer in women overall. There is some preliminary evidence, though, that the use of oral contraceptives may increase the risk of breast cancer in women with BRCA1 or BRCA2 genetic alterations.

SOURCES:
The New England Journal of Medicine, July 26, 2001; 345:235-240
The National Cancer Institute (http://www.nci.nih.gov)

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