Your genes and your health: 5 FAQs about genetic testing

October 18, 2017 | by Samir Undevia, MD

If you have family members battling cancer, you may be thinking about genetic testing to determine your risk of getting the disease.

Genetic testing can help estimate your chances of developing cancer in your lifetime. It does this by searching for specific changes in your genes, chromosomes or proteins. These changes are called mutations.

For families at risk of cancer, a negative test may help ease anxiety, while a positive test can help you make decisions and lifestyle changes to help lower your risk. A positive result may also lead your doctor to recommend you:

  • Start cancer screening tests earlier (if available for the cancer type)
  • Get screened for that type of cancer more often or get screening tests that are only used for people known to be at an increased cancer risk
  • Watch yourself closely for signs or symptoms of that kind of cancer
  • Learn about options to help reduce the risk of certain types of cancer, such as drugs or surgery

Still trying to determine if it is right for you? Here are answers to common questions about genetic testing.

How does it work?
Genetic testing is more than a two-step process. Determining whether you are at risk is the first step. Your doctor or a certified genetic counselor can help determine your risk based on your medical history and family history. A genetic counselor will sit down with you to discuss the test and explain how families inherit cancer. He/she will also discuss the pros, cons, costs and limits of testing.

What tests are involved?
Genetic tests are performed on a sample of blood, hair, skin, amniotic fluid (the fluid that surrounds a fetus during pregnancy) or other tissue. For example, a small brush can be used to collect a sample of cells from the inside of your cheek. The sample is then sent to a laboratory where technicians look for specific changes in chromosomes, DNA, or proteins depending on the suspected disorder. The results of the lab test are then sent to your physician or genetic counselor. Most test results take 2-4 weeks to receive.

What types of cancer can genetic testing predict risk for?
More than 50 hereditary cancer syndromes have been described by researchers. Genetic testing can determine a person’s risk for developing breast, ovarian, prostate, pancreatic, leukemia, thyroid, sarcoma and other cancers. Here is a list of inherited cancer syndromes for which genetic testing is available.

Who is a good candidate for genetic testing?
The American Society of Clinical Oncology (ASCO) suggests genetic testing in the following cases:

  • You have a personal or family history that suggests a genetic cause of cancer
  • The test can clearly show a specific genetic change
  • Results help with diagnosis or management of the genetic condition or cancers. For example, you may choose steps to lower your risk of the disease through surgery, medication, frequent screening or lifestyle changes.

What are the risks of genetic testing?
Like any test, there are risks involved. The physical risks associated with genetic testing are very small, except in the case of prenatal testing. But there can be emotional, social or financial consequences of the test results. In some cases, test results may create tension within a family because the results may reveal sensitive information and cause depression and anxiety. It’s important to make these decisions with your family and your healthcare team.

Remember that a positive test result does not always mean you will get cancer. A genetic test can only tell what might happen in the future. Likewise, a negative test result does not mean you have no risk of getting cancer. Your cancer risk can change over time due to your lifestyle changes, like carrying around extra weight, smoking and drinking or spending time in the sun.

Learn how to do your part to not get cancer.

How do you try to lower your risk of cancer? Tell us in the below comments.

Learn more about genetic counseling at Edward-Elmhurst Health.

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