The Distraction of Precision Medicine (March 10, 2015)
Unless you have been living under a rock recently – not that there is anything wrong with that -- the phrase “precision medicine” has at least flown past your ears. That’s because the President has recently decided that this is something that needs to have a little more federal money thrown at it.
Precision medicine is a medical model that proposes customizing medical care to the patient in front of you rather than taking a shotgun approach to the disease classification. The idea is to first understand genetic variations in disease and then to use that knowledge to tailor medical treatments to the individual patient. Ultimately the goal is to re-classify diseases altogether by grouping them by their genetic and environmental causes rather than by the resulting signs and symptoms.
Where precision medicine is currently being practiced to the greatest extent is in the field of cancer treatment. Analyzing the cellular makeup of a specific patient's tumors and then targeting that cancer with the specific therapy known to be most effective for it may be the approach that finally (about 15 years ago) turned the treatment of breast cancer from poison-and-pray into something that often now actually extends the life expectancies of those undergoing therapy.
(Actually precision medicine is currently practiced to the greatest extent in Asia, where Chinese medicine has been classifying disorders by their causes and tailoring its treatments specifically to the individual for many centuries. But I guess that's a digression.)
So medicine is all aflutter over the possibility that knowing more about the causes of disease and targeting them with more specific treatments might sometime in the next few decades result in medical care no longer being one of our leading causes of death. No one could possibly object to that. But still, there is an important point that is being lost in all this hope and promise.
For example. Right now a diabetes diagnosis “gives little insight into the specific molecular pathophysiology of the disease and its complications; similarly, there is little basis for tailoring treatment to a patient’s pathophysiology.” Meaning that when someone is diagnosed with diabetes we’d like to be able to run him through a bunch of tests and narrow down just what type of many possible variations of diabetes he has, and then use that information to figure out how best to treat him, taking into account his genetics, his current physiology, and how the disease might be expected to progress in the future. With all that in mind, here’s a speculative multiple choice question for you about this guy. See if you can answer it.
Forty years from now, in the golden era of precision medicine when we have attained the knowledge we are now pursuing, the aforementioned patient with diabetes will be most likely:
a) to have his genome sequenced so we can see whether or not his specific genetic variants suggest that his diabetes might result in blindness;
b) to be tested hourly to see whether or not taking Glucophage or Glumetza results in quicker reduction of his blood sugar to normal;
c) to have his intestinal flora analyzed to determine which probiotic would be most likely to work with his current complement of fellow travelers in order to better stabilize his blood sugar; or
d) to have to get up off his butt, start doing some walking and stop eating so many Pop-Tarts.
See? How hard was that? We don’t need to do decades of research and spend billions of dollars to know how to do a), b) and c). Because we already know that he needs to do d) and that if he does it, a) b) and c) probably won’t have to be done at all. Look at that, Mr. President! We just saved $215 million!
Our problem right now is NOT insufficient knowledge. It’s non-application of the knowledge that we DO have.
We know already HOW TO PREVENT 80% OF CHRONIC DISEASE. That is what would disappear if we all made the lifestyle-related changes that we already know about. Heck, that number even applies to individuals -- you follow the rules, you're 80% less likely to get those chronic diseases.
I’m not saying that precision medicine is a waste of time. But – well, here is another example for you.
Which of the following changes in your diet is the least likely to improve your health?
a) More lean meat.
b) More dairy products.
c) More fresh fruits and vegetables.
d) More Fruit Loops.
Do we need decades of genomic sequencing and massive clinical trials to figure that one out? We know that processed foods are bad for you. That you don't know whether you are New York-Mediterranean subtype A or B, and thus don't know if you should be shmearing margarine or cream cheese on your oversized cinnamon sugar bagel, is targeting the wrong problem. Precision medicine will be a great thing when it finally arrives, but it is not – and never will – solve our real problems of health and disease.
You want your disease precisely targeted? Follow the same diet and exercise advice that EVERYONE gets. Once you’ve done that, you can start drilling down and THEN all this individualized typing of traits and diseases will begin to mean something. Until we start to live healthy, all the technology in the world won’t make us that way.
--dr. diane holmes
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