For all that we still don’t know about cancer, we are certain of two facts:
- Five to ten percent of cancers—including some breast, ovarian, endometrial, colon, thyroid, and pancreatic cancers—are due to an inherited gene mutation, and
- The earlier you catch cancer, the easier it is to treat.
The goal of genetic testing is to identify genetic abnormalities, called gene mutations, which increase an individual’s risk to develop certain cancers. But who should get tested? Does a positive result guarantee that you’ll get cancer? And does a negative result ensure that no future screening is necessary?
This is where genetic counseling comes in. Genetic counseling is a comprehensive approach to assessing and managing an individual’s cancer risk. Genetic counselors help patients understand how mutations contribute to cancer risk and can be passed down through families; who can benefit from testing; how test results are interpreted; the probability that an individual will develop cancer or a secondary cancer; the likelihood of relatives inheriting the mutation; and appropriate screening and risk-reduction strategies, and also provides resources for support.
Chloe Farkas, MGC, CGC is a certified genetic counselor, based at the Lombardi Comprehensive Cancer Center at MedStar Georgetown University Hospital. She also sees patients at MedStar Southern Maryland Hospital Center’s Breast Health Program and the Washington Cancer Institute at MedStar Washington Hospital Center.
“I feel strongly about making medical and scientific information available to everyone,” Chloe says. “Genetics is an emerging science and it is changing rapidly. Something new is discovered almost every week.”
In the general population, the risk of having a gene mutation associated with a hereditary cancer syndrome is low. But if you have a family history of early-onset and/or rare cancer, were diagnosed with cancer before the age of 50, or have a known mutation in a cancer risk gene such as BRCA1 or BRCA2 in your family, you are a candidate for genetic testing.
Chloe’s job starts before the testing begins. “I provide information and context for the patient,” she says. “After we talk, some patients choose to have genetic testing and some don’t. For most individuals at high risk to carry a mutation, we encourage testing because a positive result may inform options for increased cancer screening and/or risk reducing surgeries. Individuals at high risk to carry a mutation are generally patients who have been diagnosed with a cancer suggestive of a hereditary cancer syndrome (i.e. an individual diagnosed with breast cancer diagnosed before age 50) or it may be a person who has not developed cancer, but whose relative carries a known genetic mutation. We try not to test individuals without a personal history of cancer who do not have a known genetic mutation in the family because it is much harder to interpret the meaning of a negative result and because it is difficult to obtain insurance coverage for genetic testing for unaffected individuals.”
It all starts with the genes. Genes tell our bodies how to function and develop. We all have two copies of each gene; one copy inherited from mom and one copy inherited from dad. A small percentage of people are born with an inherited gene mutation in a cancer risk gene, which means they have only one working copy of that gene. Because specific cancer risk genes prevent the growth of tumors or the development of cancers, people with only one working gene are not as well protected as those with two working copies of the gene, putting them at higher risk to develop cancer.
So the first step for a genetic counselor is to gather the patient’s medical and family histories, which will indicate the probability that she or he may have a mutation in a cancer risk gene. If a patient does not have cancer, Chloe assesses his or her risk of carrying a gene mutation, helps identify the best candidate in the family to undergo genetic testing, and estimates an individual’s cancer risk based on the patient’s personal and family history using risk modeling. If there is a personal history of cancer, Chloe explains possible inherited causes of the cancer and assesses the risk that the patient may develop a secondary cancer. She then helps the patient decide whether genetic testing is appropriate and whether he or she wants to pursue it.
Genetic tests are more affordable and accessible than ever before. Inherited breast and ovarian cancers are primarily caused by mutations in two genes: BRCA1 and BRCA2; Chloe provides genetic testing for those and others that are not as common.
Results are available within two to six weeks, depending on the test, and Chloe then contacts the patient to discuss the result and answer questions.
“Genetic counseling helps patients put all this information in perspective, because the details can be confusing or scary at first,” she says.
Although genetic testing accurately detects the vast majority of known mutations, no test can be 100% accurate. An individual may still carry an undetected mutation, even with a negative result; patients who are at risk based on personal and/or family history are encouraged to have regular cancer screenings to ensure that if a cancer does develop, it’s caught early. Conversely, receiving a positive result does not guarantee a person has an 100% chance to develop cancer. Genetic counselors help patients and their physicians understand the meaning of a genetic testing result. Physicians and patients can then use the information to appropriately tailor a cancer screening program.
Chloe’s interest in genetics started in college, and eventually drew her into the healthcare field. She earned a B.A. degree in chemistry and English from Case Western Reserve University, and a master’s in genetic counseling from the University of Maryland. She is one of only two cancer genetic counselors in the MedStar system in the Washington, D.C. area.
“We’re very excited to have Chloe here at MedStar Southern Maryland Hospital,” says Katerina Tsiapali, MD, a surgical oncologist and medical director of the MedStar Breast Health Program. “With genetic counseling, patients are educated and given context in which to understand the test results, so they’re prepared for all eventualities.”