Genetic Testing for Breast Cancer

Breast Cancer Genetic Testing

The last several years have produced significant advances in the field of genetic testing. Doctors are utilizing preventative measures to decrease cancer risk, and are now using genetic testing to help patients and their families understand their cancer risks. So how does generic testing work and what are the potential positive outcomes for those with a breast cancer diagnosis?  What are the concerns about the risk?

When and How Genetic Testing Is Used

Genetic testing can be considered at various stages, depending on the individual and their background. For example, an individual recently diagnosed with breast cancer may undergo genetic testing in an attempt to understand why she developed cancer and whether her family is at risk.

On the other hand, healthy women with a family history of breast cancer may want to know their risks.

Modern genetic testing can be performed using either a blood test or a saliva sample collected to look for specific genetic information. The sample is sent to a lab, where a team of specialists looks for unique genetic mutations that indicate an increased risk for breast cancer.

Today, there are two primary forms of genetic testing:

  • Single or limited numbers of gene testing which analyzes a small number of genes to test for the presence of mutations.
  • Multigene panel testing which analyzes many genes for mutations. While this field is evolving rapidly, some of the gene mutations included in these panels do not yet have clearly defined cancer risks or clear data on the impact of more intensive screening or prevention options.

While both tests are useful, many factors such as family history, personal preference, health coverage and a need for immediate results, will influence which test is most appropriate for an individual.

Benefits We’ve Seen from Genetic Testing

Georgetown University's Jess and Mildred Fisher Center for Hereditary Cancer and Clinical Genomics Research in Washington, D.C., has served as the epicenter for research to improve cancer identification and diagnosis, including the use of genetic testing.

People who test positive for mutations in BRCA1 or BRCA2 (two of the most common cancer genes) can take preventative action to decrease their risk of developing or succumbing to ovarian or breast cancer. This is one of the most compelling benefits of modern genetic testing.

There are, of course, concerns regarding the added stress of knowing one carries a mutation or from receiving an inconclusive outcome from testing.  However, multiple studies conducted at the Fisher Center have concluded that the benefits of genetic testing far outweigh those challenges, as the genetic testing results allow patients to make better-informed decisions about the most effective treatment options and course of action in their medical care.

What's more, genetic testing can also determine that some relatives of people with a known mutation in a breast cancer gene understand that they do not carry mutated genes. This can relieve a significant amount of mental and emotional stress and alleviate a person's concern about an increased risk for cancer. 

What to Keep in Mind

It is possible to test for either one gene or multiple genes associated with breast cancer. While this is an exciting possibility, choosing which test to perform can be extremely complicated, but working with a genetics counselor will help ensure you choose the right test for you.

Genetic testing is complex, and in many cases, the results of the test may have implications for other members of their family such as a sibling or cousin. Patients should keep in mind that results may not resonate in the same way with their family members and should be prepared for how to handle that conversation. A genetic counselor can be instrumental in helping to understand genetic test information and in disseminating the information gleaned from it.

Finally, it's critical to keep in mind that genetic predisposition only accounts for 10 to 15 percent of all breast cancer cases.

The Case for Genetic Testing

If you were tested over three or five years ago, you should consider getting tested again in light of the recent advances that have taken place. Genetic testing for breast cancer has the potential to increase the health and longevity of women and men around the country.

We are here to help.

If you have questions about the MedStar Georgetown Cancer Network or are ready to schedule a consultation with one of our specialists, call us at 855-546-1815 or click the request a consultation button.

Dr. Claudine Isaacs is the co-director of the Breast Cancer Program and Medical Director of the Jess and Mildred Fisher Center for Hereditary Cancer and Clinical Genomics Research at the Lombardi Comprehensive Cancer Center.

Dr. Isaacs’ extensive research covers all aspects of breast cancer, including cancer risk assessment, and novel prevention, screening and medical management strategies for women at high risk for breast cancer. Toward that end, she has served as the principal investigator (PI) or co-investigator for numerous clinical trials and grants exploring potential new treatments for early-stage and metastatic breast cancer. Dr. Isaacs also was a PI for the Cancer Genetics Network site and for the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Lombardi was one of 10 sites nationwide that enrolled patients for this trial.

Dr. Isaacs has authored over 185 peer-reviewed publications, numerous book chapters and served as editor for a seminal textbook on hereditary breast cancer, published in 2007.  Professionally, she has been a member of the Cancer Education Committee and Scientific Program Committee at the American Society of Cancer Oncology, and the Breast Oncology Local Diseases Task Force of the Breast Steering Committee of the National Cancer Institute, among others.

Dr. Isaacs received her medical degree and residency training at McGill University (Canada). She completed fellowship training in the Division of Hematology and Oncology at McGill University and a Fellowship in Breast Medical Oncology in the Division of Medical Oncology at Georgetown University.  She then joined the Lombardi faculty in the Department of Medicine (Division of Hematology and Medical Oncology) where she now is also a Professor of Medicine and Oncology. Learn more about this physician.