Genetic Testing: Knowing When to Say “When”
Prevention & Treatment There’s a lot of talk about breast cancer screening, but what about genetic testing? Here’s what you need to know.
Parades of marching activists donning pink may symbolize breast cancer awareness in the month of October, but that doesn’t mean you should stop taking steps to prevent against the disease any other time of year.
Risk at home
About 1 in 8, or 12 percent, of women in the United States alone are expected to get breast cancer at some point in their lifetime. And 5 to 10 percent of that group has a known hereditary risk factor, like a BRCA1 or BRCA2 gene mutation.
“Genetic testing has become less expensive and more widely used in women based on family history of breast cancer,” says Dr. Harold J. Burstein, an American Society of Clinical Oncology expert and the Forward Area Support Coordination Officer of the Dana-Farber Cancer Institute and Harvard Medical School. “In addition, newer genetic testing panels are looking at far more than just the BRCA1 and BRCA2 genes. In rare families, those extra genes identify risk of breast cancer.”
What’s to factor?
That growing number of genes associated with breast cancer risk includes at least 17 thought to indicate a moderate to high risk, said Michelle Jackson, a product manager for hereditary breast and ovarian cancer for Ambry Genetics, and a trained genetic counselor. Ambry offers genetic testing for diseases like breast cancer, and it aims to raise awareness of the role genetics can play in disease risk as well as health care decisions.
While sporadic breast cancer accounts for most breast cancer diagnoses in the U.S., affecting upwards of 80 percent of individuals who are mostly in older age, the familial form of the disease accounts for 15 to 20 percent. Historically, experts have thought of familial breast cancer as the result of genetic and environmental factors, and a type that occurs when a woman is in her late 50s to early 60s.
"While guidelines vary, most organizations recommend genetic testing for men diagnosed with breast cancer at any age, for women diagnosed with the disease under age 45 and individuals with Ashkenazi Jewish ancestry..."
“That’s probably a definition that’s evolving as new genes are identified,” Jackson says, “and as we discover that some of these genes aren’t as high risk as genes like BRCA1 and BRCA2.”
Timing is everything
The American Cancer Society’s latest breast cancer screening guidelines recommend a woman begin getting routine mammograms starting at age 45, and every other year between ages 50 and 70.
“Women with strong histories of breast cancer in the family, or known mutations in BRCA1 or BRCA2, should absolutely get screening, and may require additional screening with breast MRI,” Burstein adds.
Knowing when to speak to a genetic counselor or undergo genetic testing can be trickier, but experts say the choice is just as important for breast cancer prevention as is getting routinely screened.
Higher risk populations
While guidelines vary, most organizations recommend genetic testing for men diagnosed with breast cancer at any age, for women diagnosed with the disease at or under age 45, and individuals with Ashkenazi Jewish ancestry who have had breast cancer at any age. Individuals in these categories are all considered to be at a higher risk for hereditary cancer.
“I think the other big one is definitely if there’s someone already in the family who’s known to have a BRCA mutation or another hereditary cancer gene mutation—if that’s already known in the family, then other blood relatives are at risk,” says Jackson.
While diet and lifestyle factors can impact an individual’s breast cancer risk, the choice to undergo genetic testing is a personal one. Experts say this decision should be based on an individual’s personal and family history of the disease, following a discussion with a genetic counselor or knowledgeable health care provider who can determine the factors that may impact their risk.
“The one thing that’s important about hereditary breast cancer is its potential to impact people’s treatment and management,” Espenschied adds. “If someone has a family history of breast cancer and a family member who has tested positive for a mutation in BRCA1 or BRCA2, then thhey can be tested for that mutation. That way, if they test positive for the mutation, they have the opportunity to take measures to reduce their risk of breast cancer.”