I’ve discussed in a few prior posts (for example here and here) the potential downsides of doing too much testing in medicine. This is an important topic, and one that can be difficult to discuss. Patients – quite reasonably – want to feel that their doctors are listening to them, and running all reasonable medical tests to prevent, diagnose, and treat disease. Any discussion of how medical testing can sometimes actually be detrimental to your health can therefore risk coming off as being callous and uncaring. “What do you mean I shouldn’t be tested for disease x?,” a patient may think. “Don’t you want me to know if I have it or not?” Unfortunately it’s not so simple.
I’m going to take a holiday break from posting on this blog over the next few weeks. But before doing so, I’d like to share a few parting thoughts as we wrap up the year.
A few patients have recently asked me about “liquid biopsy” tests. These are a new frontier of testing in which a single blood sample is analysed for evidence of multiple types of cancer. The idea is to analyze a single blood sample and – ideally – receive reassurance. However if you got an abnormal result, you’d then be referred for further testing to either confirm or exclude a diagnosis of cancer. This is much the same process as our current prostate cancer screening program in which a man has a PSA test as part of his annual physical to indicate the possibility of prostate cancer and then, in the event of an abnormal result, is referred for further workup (e.g. a prostate MRI or biopsy) to determine if he in fact does have cancer, or if he simply has a “false positive.” However, unlike with a PSA – which checks only for prostate cancer – a “liquid biopsy” would be able to test for dozens of different types of cancer at once.
It’s wonderful to imagine a (not so distant) future in which a blood test at your annual physical can screen you for virtually every known type of cancer (including ones for which we currently have no good tools for early detection such as brain, pancreas, or ovarian) and either give you reassurance that you are cancer free, or conversely pick up a cancer in the very earliest stages and offer a much better chance for cure.
There are a number of such tests under development (the GALLERI test from Grail, and CANCERGUARD from the makers of Cologuard are two of the better known ones), and, as you can imagine, these are igniting great interest in both doctors and patients. And while none of these tests are yet to be FDA approved – nor to be covered by any type of insurance – a few are now commercially available for those who can pay out of pocket for them. Not surprisingly then, a few patients have asked me recently whether these are worth having.
I recently came across a paper that was published almost ten years ago (2017) but which I think is highly relevant and very interesting. But before I get into it, let me give a bit of context.
In honor of this week’s holiday, I’m taking the week off from writing a blog post. A happy Thanksgiving to all of my readers and patients, and I will post something more informative next week.
To my patients: we will be hosting the holiday at our house, so I will be in the area and available all weekend for any urgent matters.
We live in a weirdly politicized and polarized time, and little better illustrates this than some of the critiques we see against the “MAHA” movement (since when did removing artificial additives from the food supply become a “conservative” issue?)
But before I get into that, I want to stress that this blog – like the practice of medicine itself – is not political. On a personal level, my politics are fairly moderate, and I have at different times in my life found myself agreeing with and voting for candidates from both major parties (and, more often, being highly critical of both parties), and I certainly have a LOT of concerns with the current administration. On a professional level, my only allegiance is to good science and good medical care. In the exam room, I am neither a Democrat nor a Republican, a liberal nor a conservative, and I’ve had wonderful relationships with patients of every political stripe over the years.
I state all of this because I don’t want what I’m about to write to be interpreted as an endorsement of any particular politician or political party. Rather, I want to highlight how reasonable scientific discussion can get dismissed as partisanship when it is offered by a politician, and to once again demonstrate just how poorly our national media does of keeping the public informed about issues of science and health.
