About Direct-to-Consumer Genetic Testing for Breast Cancer Risk

By Brandie Leach, MS, CGC, LGC

In March, consumer genetics company 23andMe received the first-ever FDA authorization for a direct-to-consumer (DTC) genetic test for cancer risks. This authorization allows the company to provide testing, without a prescription, for three genetic mutations associated with a significantly higher risk of breast and ovarian cancer in women, and of breast and prostate cancer in men. Most commonly found in individuals of Ashkenazi Jewish (Eastern European) descent, these mutations are:

• the 185delAG variant in the BRCA1 gene
• the 5382insC variant in the BRCA1 gene
• the 6174delT variant in the BRCA2 gene

What can consumers expect from the test?

We view genetic testing as a complement to (i.e., not a replacement for) personal and family medical histories, capable of providing valuable insight when used appropriately. Before ordering a genetic test, we consider the following:

Is it accurate? Does the testing technology deliver the same answer every time?

Does it have medical value? Is there strong evidence that links the test results with a given disease or risk factor?

Is it useful? Are there accepted healthcare changes to make based on the result and, will the result impact life decisions?

The FDA determined that the test is accurate and provides reproducible results. For the 2% of Ashkenazi individuals that have BRCA1/BRCA2 hereditary mutations, the 23andMe test might provide information we view as medically valuable and useful. For those who are not Ashkenazi, however, the test won’t tell them much.

The FDA’s press release emphasizes that the 23andMe test looks for only 3 of the >1,000 known BRCA mutations. A negative finding does not rule out the possibility that an individual carries other BRCA mutations that increase cancer risk. A positive result might inform a patient’s conversation with his or her doctor, but should be confirmed in a clinical setting. Additional testing may be necessary in either case, and physician-geneticists and genetic counselors have the education and experience (and licensure) to make those decisions. It is also important for consumers to be aware that while BRCA1 and BRCA2 are the most common genes linked to hereditary breast and ovarian cancer, they are not the only genes. Even if an individual of Ashkenazi descent undergoes 23andMe testing and is not found to have these three mutations, there might be additional clinical genetic testing that is warranted based on the family history.

Genetic counseling remains a useful step

Genetic counseling can help people consider the risks, benefits, and limitations of genetic testing in their individual situation. With more than 54,000 genetic tests available for more than 11,000 conditions, navigating the genetic testing landscape requires broad knowledge of genetics and an understanding of the availability and relevancy of genetic testing options.

At Cleveland Clinic’s Center for Personalized Genetic Healthcare, the clinical arm of the Genomic Medicine Institute, patients are referred to genetic counseling when their providers suspect a possible genetic basis for their disease. When we meet a patient, we take a full personal and family medical history and complete a risk assessment before deciding which, if any, genetic test is appropriate.

Genetic counselors are an important source of education, support, and advocacy for patients and providers. Genetic counseling includes providing services such as:

• Helping patients understand the pros and cons of testing and treatment options.
• Working with laboratories to ensure the correct testing is performed.
• Contacting insurance companies to advocate for coverage.
• Discussing test results with patients, including prevention and disease management recommendations if the results are positive.

Increasing awareness of hereditary risk factors

One benefit we’re seeing from the DTC genetic testing trend is an increased awareness that certain diseases have a genetic component. More patients are informing their primary care providers that they have done DTC testing, and this can be an opportunity to discuss potential links between cancer risk and family and personal medical histories. Increased patient engagement may lead to a growing understanding of medical genetics among non-genetics providers, along with increased genetic literacy among consumers, which I view as a win.

Brandie Leach, MS, CGC, LGC, is a cancer genetic counselor in Cleveland Clinic’s Center for Personalized Genetic Healthcare, the clinical arm of the Genomic Medicine Institute. She is also an elected member of the Board of Directors for the Lynch Syndrome Screening Network and former president of the Collaborative Group of the Americas on Inherited Colon Cancer.