Breast Cancer | Genetic Testing

Not all genetic tests are created equal

Understanding the limitations of direct-to-consumer genetic testing for breast cancer risk

Invitae®

Published in

Health decoded

3 min readJul 14, 2021

Originally published on Invitae.com on December 17, 2018

Genetic tests that aren’t comprehensive may provide a false sense of confidence or risk for patients wanting to understand their potential for developing heritable breast cancer.

Genetic testing was initially available only to medical specialists and genetic counselors to diagnose disease. As technology improves and costs come down, genetic tests are now more accessible to anyone curious about their genetic health.

With so many genetic testing products on the market, it can be challenging to know how to incorporate the data from these tests into medical care or decisions.

A 2018 study found that 88% of patients had an increased risk for breast cancer that direct-to-consumer genetic testing wouldn’t find, and 50% found they received a false positive result from direct-to-consumer genetic testing

Research presented by Invitae scientists at the December 2018 San Antonio Breast Cancer Symposium (SABCS) showed that direct-to-consumer genetic tests have a limited ability to report on breast cancer risk.

Read on for more key findings from the study.

Direct-to-consumer genetic tests miss critical results

Portrait of an asian woman standing outside — genetic testing for breast cancer

To better understand the limitations of direct-to-consumer genetics, Invitae conducted a study analyzing de-identified test results for over 100,000 patients who had a personal or family history of cancer. Scientists wanted to see if the patients carried a variant associated with an increased genetic risk of developing breast cancer.

The study data presented at SABCS showed that 88% of patients had a variant associated with increased risk of breast cancer that direct-to-consumer genetic testing wouldn’t find.

That’s because direct-to-consumer tests only examine three variants linked to breast cancer, while clinical laboratories test for dozens of genes and thousands of variants associated with breast cancer risk.

False positives are more common than you think

Three generations of women outside at park — direct-to-consumer genetic tests

The second piece of data presented at SABCS examined the accuracy of direct-to-consumer test reports. Invitae performed clinical confirmation testing for 102 people who received a positive result from a direct-to-consumer genetic test.

50% of these patients received false-positive results from their direct-to-consumer test.

Always confirm direct-to-consumer test results with a clinical lab

Portrait of a beautiful African American woman

For anyone hoping to understand the risks of genetic conditions through a direct-to-consumer genetic test, it‘s crucial to understand the limitations of these tests.

It’s important to confirm any direct-to-consumer genetic test results with a test from a clinical lab and talk to a healthcare professional before making any medical decisions based on genetic information, regardless of whether the result is positive or negative.

If you have more questions about clinical genetic testing for breast cancer risk with Invitae, visit us on our website.

Reference

Esplin, et al. Limitations of direct-to-consumer genetic screening for HBOC: False negatives, false positives and everything in between. Poster presented at: San Antonio Breast Conference; December 4–8, 2018. San Antonio, TX.