What did you hope to learn from your genetic test … if you have ever had one?


There’s a very nice article today on the MedPage Today web site about the medical value of “at-home genetic testing” (i.e., the sorts of tests available from companies like 23&Me and some others).

In his article, entitled “At-home genetic test might change medicine“, Dr. Suneel Kamath talks about what is real and what is less real about the information we can get from such forms of testing and what people do with the information.

Let me give you an example with a quote:

A study of more than 1,000 people who used either the 23andMe or Pathway Genomics personal genetic testing kits showed that the people at higher risk for colorectal, prostate, or breast cancer based on their genetic test results were no more likely to get cancer screening, change their diet, or exercise compared to people with normal or lower risk for cancer. They did find that men with higher prostate cancer risk were three times more likely to start taking vitamins or herbal supplements compared to men of normal or low risk, despite the lack of quality evidence proving vitamins or supplements prevent prostate cancer.

Now please don’t get me wrong. There is going to be real value to the large scale databases that are being built by companies like 23&Me … because they are collecting data from millions of people and these de-identified data will have enormous utility for research purposes. However, at the same time, …

The data being collected through “at-home” genetic test kits are by no means the same as the sorts of genetic testing being done by companies like Foundation Medicine through the use of the Foundation One test or through The Broad Institute in the Metastatic Prostate Cancer Project. These types of genetic testing have real and definable goals that can be used to either affect the actual treatments used in an individual patient (as is the case with the Foundation One test) or to identify specific subsets of patients who, if treated in certain ways, may have a higher probability of specific types of clinical response.

 

3 Responses

  1. The home genetic tests are quick and easy and cheap and do provide relevant information about one’s health. Having more information, rather than less, should be encouraged. What an individual does with the info is ultimately up to them, as it should be. And, for all those who may ignore it, there will undoubtedly be many others who use the information constructively for real health benefits.

    Certainly, the home tests are not the much more sophisticated tools like the Foundation One test, but the use and value of the home tests are just getting started. I wouldn’t underestimate their significance going forward.

  2. Risk of a prostate cancer diagnosis isn’t the only use for such tests. At the risk of sounding like an ad — Color Genomics is a division of Genome Dx, the same company that offers the Decipher test. They are now offering a 30-gene panel listing the most frequently observed germline mutations in DNA repair genes.

    It includes all of the most prevalent DNA repair genetic mutations that have been found to be over-expressed in men with metastatic prostate cancer plus other genes that have been implicated in other cancers. They also look for aberrant TP53 and PTEN — two gene mutations that have been implicated in the loss of tumor suppression and loss of apoptosis, and are prognostic for aggressive prostate cancer variants. What is astounding is the price — only $249! A full genomic analysis of BRCA2 would cost somewhere between $2,000 to $3,000. By limiting their analysis to the most common site mutations, they are able to make it affordable, albeit not as thorough. It can be ordered by a physician (they will provide one if necessary). It is a simple saliva test that the patient mails in, and genetic counseling is included with the results.

    Most (7 out of 8) metastatic patients will learn nothing from this test, and it will be a waste of money. But for some who seem to have an unusually aggressive prostate cancer variant, have ductal/intraductal histology, or have had lymphovascular invasion identified at pathology, it may be worth paying for the relatively inexpensive test. It may indicate that a platin may be a preferred form of chemotherapy, or that a clinical trial of a PARP inhibitor may be warranted.

  3. My wife and I were relatively early participants in 23&Me’s combination ancestral and health sampling. This was before the FDA curtailed the health portion of the test; thus we were able to view our relative risks for hundreds of diseases with a heritable component. Since we knew of numerous relatives’ medical histories we were amazed to see higher risks for diseases already known in our two families and it instantly flagged my much elevated risk for prostate cancer.

    For $99, we thought it a fantastic bargain. We were only sad to see the FDA barge in for what we still believe were very dubious reasons. It is still possible to buy 23&Me’s combination kit and then process its raw data through a third party program to derive much more specific health risk information. However, when we compared the two using my wife’s and her sister’s more recent test, we were disappointed in how limited its results were compared to the earlier 23&Me-provided results my wife received.

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