Genetic tests: Approach with caution
Posted: Tuesday, February 12, 2008 10:24 AM by Elizabeth Chuck
By Robert Bazell, NBC News chief science correspondent
One of the most important lessons I’ve learned in many years of reporting on health and science is that the advice to talk to your doctor – routinely offered up by government officials and others when a complex issue arrives – can be close to useless.
No doubt physicians know a lot. But they can’t know everything – and especially in fields that have developed rapidly after they completed their training.
Nowhere is this more apparent than in the issue we are covering tonight in the second part of our series, “Who We Are: The Truth about DNA.” Genetic tests for hundreds of diseases are now hitting the market place and many of the companies have been advertising them directly to the public and heavily to physicians.
The problem is, correctly interpreting the results can be complex and difficult. Many physicians simply don’t know how to, and the consequences can be dire. Women who test positive for a breast cancer gene, for example, often elect to have their breasts and ovaries surgically removed. But a negative test can give a false sense of security that might lead a woman to forgo routine mammograms that could have detected early breast cancer and saved her life. Moreover, the breast cancer gene test, which costs more than $3000, is often simply not necessary.
The biggest seller and advertiser of the tests is Myriad Genetics. Its CEO, Dr. Gregory Kritchfield, tells me the company advertises because “We feel a tremendous obligation from a public health perspective to get the information in the hands of individuals so that they can have the appropriate medical interventions take place."
But Ellen Matloff, a genetic counselor at Yale, says “If you watch these ads on TV, you would think that you're a candidate for this test, even if your neighbors had breast cancer and you're just concerned about getting it. And that's a misnomer. It's not accurate.”
Lax government regulation
At least there is no argument about the accuracy of the tests from Myriad Genetics. Dozens of other companies are selling tests which many scientists say can be inaccurate and lack value for predicating much about genetic diseases. There is a frightening lack of government regulation.
Even with a good test, there are potential pitfalls. The results, as Matloff points out, is “not a yes or no answer like a pregnancy test,” but rather a series of subtleties.
One of the biggest challenges is that if you take a genetic test, it can affect your parents, children, brothers and sisters even cousins. Do they know you are taking the test? Do they want you to share the information with them and will they know what it means? Do you want to share it?
Because of all of these and many other complexities, experts in genetic medicine advise that everyone gets competent counseling BEFORE they decide to take a test.
You can certainly get counseling from some doctors. But look that doctor in the eye and ask if he or she is truly understands the issues and is comfortable with the counseling.
Another option is to find a certified genetic counselor. These are people who are trained to understand the results and are likely the best qualified . You can find one from their certifying organization, the National Society of Genetic Counselors (http://www.nsgc.org/)
Genetic testing for diseases is an area where the science is far ahead of society’s ability to handle it.
Editor's note: Robert Bazell's report on the growing number of genetic tests airs tonight on the broadcast. Tomorrow night, he takes an in-depth look at how DNA evidence is shaking up the world of forensic science. Read a preview here.
