Approximately 12 percent of women will develop breast cancer at some point in their lives, according to the National Cancer Institute . For some women, that number is much higher.
Around 55 to 65 percent of women who inherit a harmful BRCA1 gene mutation and around 45 percent of women who inherit a harmful BRCA2 mutation will develop breast cancer by age 70. These statistics are leading more women to consider genetic testing.
However, not everyone is a candidate for genetic testing. The mutations are relatively rare in the general population, so individuals who do not have cancer should only be tested if their family history indicates a possible BRCA1 or BRCA2 mutation. Some indications that may lead a physician to recommend genetic testing include a family history of:
- Breast cancer diagnoses before age 50
- Cancer in both breasts
- Both breast and ovarian cancers
- Multiple breast cancers
- Two or more primary types of BRCA1- or BRCA2-related cancers in a single family member
- Male breast cancer
- Ashkenazi Jewish ethnicity
What are BRCA1 and BRCA2?
BRCA1 and BRCA2 are human genes that produce tumor suppressor proteins that help repair damaged DNA, playing a role in ensuring the stability of the cell’s genetic material, according to the National Cancer Institute. When either of these genes mutate, the protein product isn’t made or doesn’t function correctly and, therefore, DNA damage is not repaired properly. Because of this, cells are more likely to develop additional gene changes that can lead to cancer.
In some cases, there are other genes associated with breast or ovarian cancer.
“Most breast and ovarian cancers associated with identifiable gene mutation are related to BRCA 1 and 2, but there are less common genes which are included in multi-gene panel testing,” said Dr. Carolyn Menendez , breast cancer surgeon and co-medical director of Novant Health’s cancer risk clinic in Charlotte, North Carolina. “The testing strategy is determined by the genetic counselor and based on a patient’s individual risk.”
How is testing performed?
Genetic testing can be done via blood or saliva sample. Most insurance will cover the cost of genetic testing, and the coverage typically can be determined before processing the DNA sample. Most physicians encourage genetic counseling before genetic testing.
In a genetic counseling appointment, a genetic counselor reviews family history, determines the likelihood of identifying a genetic component to the cancer in the family and discusses the benefits, risks and limitations to pursuing genetic testing.
If an individual ends up testing positive for the BRCA1 or BRCA2 gene, their physician may suggest several proactive treatment options. These options include enhanced screening, risk-reducing (prophylactic) surgery and even chemoprevention.
“If a woman has a greater than 20 percent lifetime risk for breast cancer, or has tested positive for the BRCA1 or BRCA2 gene mutation, I would recommend a breast MRI in addition to their annual mammogram,” said Dr. Nicole Abinanti, director of women's imaging at the Novant Health Cancer Center in Charlotte, North Carolina.
Abinanti added, “For enhanced screening, I recommend tomosynthesis, or 3-D mammography, for all women. The data collected helps decrease overlapping tissue and call-back exams. This helps to decrease anxiety when it comes to mammograms as well as increase cancer detection.”