Triple-negative breast cancer is notoriously difficult to treat. It grows aggressively, and it lacks the three most common markers (estrogen and progesterone receptors and the HER2-neu protein) that we often target in our treatments. Some of our gold-standard treatments don’t work well enough against this type of cancer, and national survival rates are lower within five years of diagnosis compared to other forms of breast cancer.
As such, we are continually researching better ways to screen for and prevent this type of breast cancer. So when an August 2018 study published in the Journal of the National Cancer Institute found that several previously unknown genetic mutations were associated with a higher lifetime risk of triple-negative breast cancer, we were eager for good news. Some popular media outlets suggested that genetic testing could help identify more at-risk women and lead to better prevention strategies.
There’s no doubt that the discovery of these mutations is a potential breakthrough for triple-negative breast cancer prevention. But not every woman should rush to genetic testing to determine her risk. While there seems to be more benefits for women who previously have been diagnosed with triple-negative breast cancer, the results of genetic testing may not be as helpful for women who have never had the disease.
Benefits of genetic testing for triple-negative breast cancer survivors
The current guidelines from the National Comprehensive Cancer Network (NCCN) state that women should be referred for genetic counseling if they:
- Have been diagnosed with triple-negative breast cancer before age 60
- Were diagnosed with any type of breast cancer at or before age 50
- Have a close family member, such as a mother, grandmother, or sister, who has been diagnosed with breast cancer or ovarian cancer
- Have been diagnosed with two separate breast cancers
If a patient is referred for genetic counseling, the counselor will conduct a detailed review of her family history to determine whether she might benefit from genetic testing. We currently test for a number of known genetic mutations, including mutations to the BRCA1 and BRCA2 genes, which are known to greatly increase a woman’s risk for breast cancer. With the newly discovered mutations from the previously mentioned study, we potentially can add additional mutations to our routine screening and get a better idea of how likely a woman is to develop another triple-negative breast cancer. Patients who are found to be at high risk might benefit from more intensive screening with the addition of breast magnetic resonance imaging (breast MRI) tests to standard mammogram so we can find the disease earlier.
