Connections: Validate genetic testing for breast cancer | Fall 2019

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From the OHSU Knight Cancer Institute

HCM Connections Magazine Jone Sampson headshot

Jone E. Sampson, M.D.

Dr. Sampson is a clinical geneticist and the director of the Cancer Genetics Clinic at the Knight Cancer Institute. Together with a team of genetic counselors, she sees patients who are referred for counseling and genetic testing for hereditary cancer syndromes.

Genetic risk interpretation is a complex and frequently changing study. A recent explosion in advertising to the public encourages patients to learn their “health predispositions” through DNA testing via various direct to consumer genetic testing companies. Though getting this information may sound useful to patients, the results are ripe for confusion and inaccuracy.

Direct-to-consumer genetic tests

You may have experienced patients arriving for their clinical visits with a sheaf of papers from DNA testing businesses, asking for help in understanding the implications of the results. Some services are valid genetic testing labs, while some are less rigorous. For example, one consumer service only tests for the three founder BRCA 1/2 mutations found in the Ashkenazi Jewish population rather than sequencing the whole BRCA 1/2 genes. If the person isn’t Jewish, she may get a potentially false impression that she doesn’t have a breast cancer gene mutation.

If a patient brings results from a consumer DNA testing service that is positive for a mutation, providers should determine if the testing lab was certified by a Clinical Laboratory Improvement Amendments, or CLIA. If not, validate the results through a CLIA-certified lab or refer the patient to genetic counseling.

Considerations for ordering genetic testing for breast cancer

Genetic testing can determine if a person’s breast cancer is the result of an inherited gene mutation. If the result is positive, it can be used to guide the person’s own management, as well as inform her/his relatives to consider genetic testing to find out if the mutation was passed on to another generation. Because most cancers develop due to acquired changes that cannot be passed to children, it is more beneficial to test the parent with cancer rather than their unaffected children.

There are a variety of hereditary cancer gene panels available, some specific to breast cancer risk genes and others including genes associated with other cancer types. If ordering a breast cancer panel, primary providers should become familiar with the genes on the panel and read the reports to understand the repercussions for specific mutations. Providers should verify if the finding was a deleterious or suspected deleterious mutation, not a variant of uncertain significance, or VUS. Finding a VUS is common among large-scale gene panels and shouldn’t be used in clinical decision-making because there isn’t a known connection to disease.

Also, pre-counseling with patients before ordering a genetic panel should include:

  • Hereditary implications: The information may affect not only the patient but his/her family members.
  • Insurability issues: Life insurance and long-term disability providers can refuse coverage or charge higher rates to people with gene mutations.
  • Further testing or counseling: The National Comprehensive Cancer Network publishes recommendations for surveillance and risk-reducing options for individuals with high- and moderate-risk breast cancer gene mutations. A positive result may necessitate a referral for genetic counseling.

Comprehensive genetic counseling and risk assessment

The OHSU Knight Cancer Institute is the only NCI-designated Comprehensive Cancer Center in Oregon with board-certified medical geneticists. We offer clinical testing for mutations in genes associated with hereditary breast cancer and other hereditary cancer syndromes. We provide counseling regarding the benefits and risks of testing. With our specialized expertise and knowledge, we can give patients accurate information from the start.

We are also aligned with the diagnostic, medical and surgical oncology professionals for a seamless experience for the patient. We also offer telemedicine appointments from Medford.

When to refer

If there is a concern about hereditary breast cancer, patients may benefit from genetic counseling and testing. Some of these risks include:

  • All women diagnosed with breast cancer younger than 50 years old, regardless of history.
  • Patients who have a deceased first-degree relative diagnosed with breast cancer younger than 50 years old that did not have genetic testing.
  • Patients who have two or three near relatives who died of breast cancer without genetic testing.
  • Patients of Ashkenazi Jewish descent.

Contact us

From the latest technology to the newest drugs that are increasing survival, OHSU Knight Cancer Institute offers a full range of options for cancer patients. We are always available to answer questions.

Please call the OHSU Physician Advice and Referral Service at 5034944567.

To refer a patient, please fax to 5033466854.