Medical Genetics: Genetic Testing for Cancer Risk

Genetic tests can help predict your risk for some kinds of cancer. They can help you make health care choices based on your cancer risk. They can also tell you if you have cancer-risk related genes that could be passed on in your family. But no genetic test can tell you for sure whether you'll get cancer.

You can get genetic testing by working with your doctor. And there are companies that sell genetic test kits you can use at home. Learn about genetic testing before you have it done. Know what you can and can't expect this testing to tell you. Most experts advise working with a genetic counselor. They can talk with you about the pros and cons of testing before it's done.

Should you be tested for genes that can show cancer risk? The American Society of Clinical Oncology (ASCO) advises it if:

• You have a personal or family history that may be linked to a genetic cause of cancer
• The information you'll learn from a genetic test is useful. It can show a specific gene change that's been studied.
• The test results will help with diagnosing, treating, or managing a cancer in you or family members at risk for cancer
• Genetic counseling will be done before and after genetic testing

Home test kits can be confusing. Some of them don't always give useful or even valid results. They may give you information that won't help you prevent or treat any disease. Instead, they may just worry you. Talk with your doctor to understand the risks and benefits of using a home test kit before buying one. Also share the results with them if you do use one. Your doctor can help you:

• Understand the results of the test
• Compare the test results with family history and other factors
• Get follow-up care if needed
• Explain when there are no follow-up care choices for certain results

Also check out the company offering the tests. Is a "free" test linked to product purchases from the company? Must you commit to a customized diet or supplement plan that's based on your results? Understand if and how they might use your results, too. Will they be shared with anyone? Protect your privacy.

It's a big decision to have genetic testing. It can cause relief or stress. For example, a negative test result in a family with a known gene problem may give you a lot of relief. You may feel better about your personal cancer risk and the risk to your children. This can help you prevent unneeded medical procedures. A positive test result can help you prevent or manage a disease. It may help you make decisions about your cancer screening plan. It may also help you take steps to lower your cancer risk.

But getting your genetic test results can be confusing and stressful. A negative result may lead you to think you don't have a higher risk for a certain kind of cancer. But you may have a higher risk because of other factors. Sometimes test results may be unclear. This is called a ‘variant of uncertain significance.’ It should not change your care plan. You may have follow-up tests for reclassification.

It's very important to fully know what the tests may or may not tell you before you have them. You should also know the costs and if your insurance will pay for testing.

Before you decide to have genetic testing, talk with a genetic counselor. They can take you through pretest and post-test counseling. They can tell you about the medical, social, and legal issues that can be linked to the results. To find a genetic counselor, talk with your primary doctor. Or reach out to your local hospital system.