Article: Genetic testing and the future of medicine

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Why are we covering this article?

Genetic testing is a medical tool that can help people learn about their risks for diseases and conditions. Many people don’t understand how genetic testing works or its implications. Katie Couric Media published an interview with Dr. Robert Steiner, a genetics expert who raises awareness about genetic testing, answers common questions and dispels myths.

Genetic testing identifies changes in people’s DNA. It is done by taking a sample of a person’s saliva, blood or tumor tissue. The sample is then sent to a laboratory where the testing is performed. Results are shared in a report that summarizes the findings.

Genetic testing can change a person’s medical care. It can help them understand their risk for a disease before it develops. Healthcare providers use genetic testing results to empower people to make medical decisions that lower their risk or even prevent them from developing a disease. Katie Couric would likely agree, as she lost her first husband to colon cancer when he was 42. (Whether he had a mutation that increased his risk of colon cancer is not publicly known).

Clinical genetic testing

Dr. Steiner discussed “clinical genetic testing.” These tests help diagnose certain diseases or conditions or help people understand their health risks and make medical decisions. Clinical genetic testing requires a prescription by a healthcare professional.

Direct-to-consumer genetic testing

Direct-to-consumer tests such as 23andMe or Ancestry can help you learn about your ancestry or find long-lost relatives. You can order an online direct-to-consumer genetic test without a prescription.

While some direct-to-consumer genetic tests advertise that they test for genetic mutations that increase your risk of some diseases, Dr. Steiner emphasizes that direct-to-consumer genetic tests only look at a small segment of your DNA. For example, of the almost 8,500 known mutations in the BRCA1 and BRCA2 genes, 23andme only looks for three. Dr. Steiner also points out that direct-to-consumer testing does not involve a healthcare provider to help you understand your results.

FDA guidelines recommend that people who test positive for a mutation found by a direct-to-consumer genetic test also have clinical genetic testing (with a qualified healthcare professional) to confirm those results. You can read more about some of the issues with direct-to-consumer genetic testing in our XRAY review here.

What should you know before you have clinical genetic testing?

Genetic counselors are experts who can help you better understand the pros and cons of genetic testing based on your family history and inform your decision about whether or not to have testing. Clinical genetic testing may increase your stress and anxiety. Or it can help you make informed medical and lifestyle decisions to reduce your risk of disease.

Dr. Steiner emphasizes that some people may not want to know whether they are likely to develop a disease before they have any symptoms. He uses the example of  Alzheimer’s disease, which has no known cure. He points out that ideally, clinical genetic testing and its implications should be discussed with healthcare providers before making any type of genetic testing decision.

Who should have clinical genetic testing?

There may be times during your lifetime when you are asked to think about whether clinical genetic testing is right for you. This might occur during a pregnancy, after a cancer diagnosis, or if you have multiple cases of cancer or other diseases in your family. Guidelines that help healthcare providers identify people who should consider genetic testing vary by disease and condition and are updated often. 

Genetic testing for hereditary cancer risk

National guidelines outline who should consider genetic testing for hereditary cancer risk. People with cancer in their family may qualify. In some situations, having even one family member with a rare or young-onset cancer may signal the presence of an inherited mutation in the family.

More common signs of hereditary cancer include:

• Multiple cases of cancer on the same side of the family, especially breast, colorectal, endometrial or ovarian cancers.
• Cancer diagnosed before age 50, especially breast, colorectal or endometrial.
• Rare cancers at any age, including:
  • ovarian
  • pancreatic
  • male breast
  • metastatic prostate

How accurate is clinical genetic testing?

Clinical genetic tests are technically very accurate. However, sometimes understanding the results is challenging. Dr. Steiner explains that clinical genetic testing may not give a patient the results they were hoping for. Sometimes it is not clear whether a mutation increases the risk of cancer or not. This means that science and healthcare professionals don’t currently know if that particular mutation is disease-causing or harmless.

As science and technology evolve, so do the understanding of genetics and mutations in our bodies. This is why it is important to keep in contact with your genetic counselor or healthcare providers, who are updated on the latest information in this field.

The future of genetic testing

Dr. Steiner is optimistic about the future of genetic testing and how it can impact healthcare care. “I think in the not-too-distant future, everybody will have comprehensive genetic testing done in order to prepare healthcare providers for any future issues a patient might develop.”

When that happens, genetic testing will be used more often to help people and their healthcare providers prevent unexpected diagnoses.

What does this mean for me?

Genetic counselors are highly trained experts who can help you learn if the diseases in your family, including cancer, are hereditary. They can help you decide which test is right for you and clarify your results and your overall risk of disease.

Ask your doctor for a referral to a genetic counselor if any of the following apply to you:

• You have multiple or rare cancers in your family.
• You had a genetic test that indicated a risk for a disease (including direct-to-consumer genetic testing) and have not spoken with a genetics expert or do not understand your results.
• You do not know your family history of cancers or you are considering genetic testing.

There is a shortage of genetic counselors in the US. If you live in an area where you do not have access to a genetics counselor, ask your healthcare providers if other options, such as a telehealth appointment, are available for genetic counseling.

Because hereditary diseases like cancer run in families, it is important to exchange medical information with your relatives. They may have important information about your family's history of cancer. Similarly, your medical records or genetic test results may provide clues to help your relatives make their medical decisions about their healthcare.

References

Pinto, Emily. What Exactly is Genetic Testing…And Could It Change the Future of Medicine? Katie Couric Media; 2023. Published June 9, 2023.

Reidy-Lagunes, D. (Host). (2023, April 6). Katie Couric’s Cancer Journey: From Grief to Advocacy to Her Own Breast Cancer Diagnosis. (No. 37) [Audio podcast episode]. In Cancer Straight Talk from MSK. The Paley Center for Media.

Disclosure: FORCE receives funding from industry sponsors, including companies that manufacture cancer drugs, tests and devices. All XRAYS articles are written independently of any sponsor and are reviewed by members of our Scientific Advisory Board prior to publication to assure scientific integrity.

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posted 9/28/23