Understanding your risk: Genetic testing for breast cancer

Cyndi Pierre knew that her family history put her at increased risk of breast cancer. Both her mother and sister are survivors. So she did what she could to reduce her risk—she ate well, exercised, and got regular mammograms. She even got tested for the BRCA “breast cancer” gene mutations, which increase a woman’s risk of breast cancer exponentially—it was negative.

“I thought I had covered all my bases, but I couldn’t shake this nagging feeling,” Pierre told FoxNews.com.

Pierre, 45, from Rogers, Ark. wanted to have an MRI, but her insurance wouldn’t pay for it because her risk of breast cancer wasn’t high enough.

Pierre’s nurse practitioner suggested a new genetic test, called BREVAGen, which analyzes seven genes that have been associated with breast cancer, but to a much smaller degree than the BRCA genes.

BREVAGen showed Pierre’s lifetime risk of developing breast cancer was 33 percent—which may not sound high, but it’s nearly three times higher than the average woman’s. With those results, she sought approval from her health insurer to get a MRI, and found that she had early stage cancer.

The new test combines a DNA sample, via a swab of your mouth, and a traditional assessment of personal and family risk factors. It may be most useful for women with known risk factors, such as a family history.

The average woman has a 12 percent (or 1 in 8) risk of developing breast cancer if she lives to 95 years old. But women with a strong family history of breast cancer and other risk factors that increase her lifetime exposure to estrogen, may have a risk ranging from 10 percent to 30 percent or more over a lifetime, and current risk assessment models are not sensitive enough to pinpoint these risks.

Having the BRCA gene mutations, as Angela Jolie famously revealed earlier this year increases the risk to between 60 and 90 percent! But researchers have found more subtle mutations, called SNPs, that increase your risk incrementally.

In cancers that don’t have a strong BRCA mutation, it’s not a single mutation that leads to the disease but many individual SNPs, which contribute a small, but measurable risk. BREVAGen tests for seven SNPs.

According to a study in Caucasian, postmenopausal women, BREVAGen reclassified 64 percent of women with intermediate risk. That means that 37 percent of women with intermediate risk were bumped down into a lower risk group, and 27 percent were bumped up into a higher risk group.

“We’re trying to transition from a general impression of a woman’s risk to a factual one,” said Dr. Joel Evans, an OB-GYN and director of the Center for Women’s Health in Stamford, Conn.

Knowing your individual risk could help you make decisions about screening and testing, and lower your anxiety if your risk was reduced by the test.

“If we find out someone is at increased risk, we do increased surveillance, and depending on the risk, a woman might be a candidate for taking drugs that prevent breast cancer like tamoxifen,” said Evans, who receives speaking honorariums from Phenogen, which markets the test.

But some experts warn that there’s no data showing that the test makes a difference in survival.

“The study didn’t give women the test, follow them for many years, and see if their test predicted correctly, and how many times was it wrong,” said Dr. Debbie Saslow, director of Breast and Gynecologic Cancer at the American Cancer Society (ACS). “We don’t know how many times the test was wrong or how accurate it is. More data and research is needed.”

In addition, because the test was validated in a study of Caucasian, postmenopausal women,  it’s not known whether the results can extend to others.

Phenogen estimates that more than 3,000 women have been tested with BREVAGen in the U.S. The test itself costs $2,200 without insurance, and is covered by some insurance companies.

For more information, visit BREVAGen.com.

Laurie Tarkan is an award-winning health journalist whose work appears in the New York Times, among other national magazines and websites. She blogs about the Affordable Care Act for the WellBeeFile. Follow her on Twitter and Facebook.