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Should You Take a Home Test for Breast Cancer Risk?

The FDA just gave approval for the company 23andMe (named for the 23 pairs of chromosomes in our DNA) to sell a direct-to-consumer BRCA gene testing kit. The BRCA (BR: Breast CA: Cancer) genes can be dysfunctional or “mutated,” increasing risk of cancer, most commonly breast and ovarian.

23andMe’s ad spots have been running frequently on TV lately. Their slogan “You’ve got one body. Take care of it.” resonates well with today’s health-conscious consumer.

There are several of these companies already on the market, such as Color. The difference now is that a person can initiate the test herself, receive the results, and never speak to a doctor or genetic counselor.

So what’s the problem?  Privacy is good, especially in the current climate where “preexisting conditions” threaten to skyrocket insurance costs, right?

Well, testing on your own can lead to wrong conclusions.

It all goes back to the false positive, false negative situation. These home diagnostic tests rarely have false positives, but they can have “false” negatives for gene mutations that they cannot and do not test for. The 23andMe testing only looks for three BRCA mutations (which, it turns out, are also the three that occur the most often among people of Ashkenazi, or Eastern European Jewish, ancestry). These three are not necessarily the most common BRCA mutations for the general population.

In other words, this negative test is far from conclusive. It doesn’t mean that a person will never get cancer.  And, it doesn’t not rule out the possibility of other BRCA mutations that increase cancer risk. But it can rule out the mutations that are most common among a small but significant segment of the U.S. population.  Unfortunately, it might give one a false sense of security.

Donald St. Pierre, the acting director of the FDA, explains: “While the detection of a BRCA mutation on this test does indicate an increased risk, only a small percentage of Americans carry one of these three mutations and most BRCA mutations that increase an individual’s risk are not detected by this test. The test should not be used as a substitute for seeing your doctor for cancer screenings or counseling on genetic and lifestyle factors that can increase or decrease cancer risk.”

If a person receives a positive result, then she should go for repeat testing ordered by a doctor or genetic counselor before making decisions about what to do with the information.  This might be really hard to do when beset by the panic that might immediately set in with the “positive” result.

There are also other (non-BRCA) genetic mutations that these home kits do not test for. When there is cancer “in the family,” genetic counselors are the best people to discuss risk and testing.

The bottom line is that home genetic tests for mutations are not great tests.  Information is empowering if used properly, but $199 is a lot of money to spend on opening up Pandora’s box without a team providing support. Genetic testing should be done and interpreted by professionals when they will be used to make medical decisions/non-decisions.

You’ve only got one body. Use your head when taking care of it.

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