Testing someone’s genetic makeup to learn more about the person’s predisposition to cancer is becoming a more common practice. But undergoing these tests could have both positive and negative outcomes for the patients. We spoke with Dr. Andrew Horodner, oncologist with
Cancer Care Associates, to get the latest information on genetic testing: who should be tested, where to get tested, and what you should do with the results.
What exactly is genetic testing and why is it becoming more popular?
AH: Most cancers develop from mutations that occur well after we are born and may result from environmental exposures (somatic). However, some mutations may already exist in our DNA when we are born (germline).
Genetic testing refers to testing an individual for a germline—or hereditary—mutation that can be passed on to offspring. As technology advances and more is discovered about certain hereditary mutations that increase an individual’s cancer risk, physicians and patients become more empowered to be able to test for these mutations and perhaps make therapeutic decisions with the results.
What exactly is the doctor looking for when a patient is genetically tested for cancer?
AH: The doctor is looking to see if the patient’s germline cells (not the tumor itself) harbor a genetic blueprint mutation (change in the DNA) that may increase that patient’s risk for a particular cancer or cancers. This test is typically done on a blood sample or swab inside the cheek.
If you are interested in this testing, whom should you speak with first?
AH: In the case where a person does not have cancer (but has a strong family history of cancer), this person may be best served by meeting with a genetic counselor or medical geneticist who can review the family history (pedigree). The counselor/geneticist can then estimate the person’s risk of having a specific mutation and discuss the pros and cons of genetic testing and the exact implications of the testing.
What are the positives and negatives of getting tested?
AH: Potential benefits: If a person knows he or she has a mutation that may significantly increase the risk for a specific cancer or cancers, the person can be proactive. They may undergo more aggressive screening procedures to detect cancer at an earlier age or earlier/more treatable stage. The person may also take steps, such as preventative surgery, to decrease/prevent cancer from occurring.
If a positive mutation is found, then other first-degree relatives can be tested so they can be empowered with the same information. Some people may also use the information when making decisions regarding family planning.
Potential disadvantages: Testing and reviewing the results can lead to significant anxiety. Just because a person has a mutation does NOT necessarily mean that he/she will develop cancer. Therefore, interpretation of results is not always black-and-white. With the help of the physician and genetic counselor, people should review the results and their significance.