Physicians primarily consider a womans age at diagnosis and her familys cancer history when determining whether to recommend genetic testing. A woman diagnosed with breast cancer before age 50, for example, or a healthy woman with several close family members who have had breast or ovarian cancer, is more likely to be referred for genetic testing than a postmenopausal woman with breast cancer and no other risk factors.

For the study, Kurian and Stefanick and their colleagues set out to compare the prevalence of cancer-associated mutations in 10 breast-cancer risk genes, including BRCA1 and BRCA2. They compared 2,195 women who were diagnosed with breast cancer at an average age of 73 with 2,322 women without breast cancer.

The data for the study came from more than 4,500 participants in the long-runningWomens Health Initiative. The initiative enrolled more than 160,000 women ages 50 to 79 throughout the United States between 1993 to 1998 to conduct the largest study of postmenopausal health in the country. Stefanick served as chair of the initiatives steering committee for most of the project.

The researchers found that about 3.5% of the women with breast cancer in their study had a cancer-associated mutation in at least one of the 10 genes, compared with about 1.3% of women without cancer. When they narrowed their focus to just the BRCA1 and BRCA2 genes in women diagnosed before age 65, they found that about 2.2% of women with breast cancers had cancer-associated mutations, versus about 1.1% of those without breast cancer.

Only about 31% of those women with cancer and 20% of those without cancer, both with BRCA1 or BRCA2 mutations, were likely to have been recommended for testing under the current guidelines of the National Comprehensive Cancer Network.

Now we know that the prevalence of cancer-associated BRCA1 and BRCA2 mutations in women diagnosed with breast cancer after menopause rivals that in women of Ashkenazi Jewish descent a population that is currently encouraged to discuss genetic testing with their doctors, Kurian said. We finally have a read on the likely benefit of testing this most common subgroup of breast cancer patients.

Researchers from Myriad Genetics Inc., the University of California-San Diego and the State University of New York contributed to the study.

The research was supported by Myriad Genetics, the Suzanne Pride Bryan Fund for Breast Cancer Research, the Jan Weimer Faculty Chair in Breast Oncology and the BRCA Foundation.

Read more here:
Older women with breast cancer may benefit from genetic testing - Stanford Medical Center Report

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