Diagnostics

How effective is genetic testing if doctors aren’t always sure how to interpret it?

“Our ability to sequence genes has gotten ahead of our ability to know what it means,” said Eric P. Winer, the director of the breast oncology program at Harvard’s Dana-Farber Cancer Institute.

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Genetic testing is becoming increasingly more prominent in healthcare treatment, especially considering Obama’s $215 million personalized medicine initiative. But how helpful will genetic data be if many doctors don’t know how to use it?

This dilemma is particularly relevant for those facing a breast cancer diagnosis with the BRCA1 and 2 genes.

The New York Times shared the story of Angie Watts, who was diagnosed with breast cancer, was about to begin radiation after a lumpectomy, and a doctor told her that a genetic test revealed she had inherited an alteration in a gene needed to repair DNA. Because radiation breaks down DNA, the doctor believed radiation could actually increase the chances of her cancer growing, and he urged her to have a double mastectomy.

Before making a decision, Watts reached out to a professor of genetics and medicine at North Carolina. He told her that that was incorrect, the mutation wouldn’t be harmful, and he believed she should go ahead with radiation.

In this situation, it’s up to the patient to decide what to do, but how can one make an informed decision when those advising her aren’t consistent?

“Our ability to sequence genes has gotten ahead of our ability to know what it means,” Eric P. Winer, the director of the breast oncology program at Harvard’s Dana-Farber Cancer Institute, told The Times.

There is genetic testing of patients to see if they inherited mutations that predisposed them to cancer, and there is genetic testing of cells from the cancer to look for mutations that drive the tumor’s growth. Both are areas where there can be misinterpretation or limited treatment options. Genetic testing can be very valuable, but it can equally provide fear for a patient without much actionable advice.

“The stakes are very high,” said Dr. Evans, the geneticist who counseled Ms. Watts. “You have inherently nuanced and confusing tests and widespread ordering and interpretation by doctors who aren’t really equipped to do so,” he said. “The situation is ripe for overinterpretation and misinterpretation.”

As of now, it makes sense to order these tests, but patients need to be prepared to experience question marks with the process. Things will surely continue to get more reliable, but for now, it appears that no one should put all of their eggs in one basket when it comes to genetic testing and how their doctor might interpret the results, especially when it comes to putting your body through something like radiation.

Photo: Flickr user Micah Baldwin