Why are screening tests controversial?

Your heart health in a heartbeat – Episode 2

Mammograms, PSA tests, heart scans, lung scans are all subject of debate and controversy.  Why is that?  Join me as I clarify the reason why screening should not be viewed only from the perspective of public health,


Today, I’d like to talk about screening tests in general and why there seems to be so much debate and confusion about them.  It seems that every other week there is a new report in the media raising doubt about the value of this screening test or that screening test, whether it’s mammography, the PSA test for prostate cancer, colonoscopy, heart scans, or what have you.  And you hear one group of people advising one way and another advising another way, and it’s very confusing.

So how do we make sense of that?  Let me give you my thoughts.  In my mind, the confusion comes from not making a distinction between public health and clinical medicine.

When people consider screening from a public health perspective, it’s a top-down recommendation made according to a very simple rule.  Typically it’s going to be something like “All men over age 50 should get a PSA test” or “All women over age 40 should get a mammogram” so the whole process lacks any nuance and is kind of mindless.

Well, when you do things mindlessly, the benefits may not be that great.  The test may have limitations: for example, a mammogram can show a nodule that turns out not to be cancer.  It may cause the person to undergo a biopsy that, in retrospect, and from a public health standpoint, may seem unnecessary.  Or, the test may identify a cancer, but not all cancers will be lethal.  Some prostate cancers takes so long before they cause symptoms that it is more likely that the person will die of something else, so again, from a public health standpoint, the screening seems like a waste.

And of course there are costs associated with the testing and with the consequences of testing.  So the public health authorities and the insurance companies have to decide what makes sense for them and they have to get into a very complicated cost-benefit analysis.  All this is a very complicated problem because putting a dollar value on a potential life saved is a tricky business.

Now, if you look at things at the individual level, in the context of a single patient coming to the doctor and don’t make a public health issue out of it, then things become much simpler.  And let me give you 3 ways in which I think that makes a big difference.

First, if you come to me and ask me “Am I healthy?”  Well to answer that question I’m not going to immediately order tests just because you have a certain age.  I first have to get to know you, understand what your health concerns are, understand what your expectations are, and know your relevant medical history and life circumstances.

Once we’ve done that, then I can tell you what I think is the most appropriate screening procedure for whatever condition we want to discuss.  I can explain the tests that are available, and if the tests have any limitations, we can talk about that as well and about the costs.  We don’t need to adopt an assembly line mentality.  That’s not very good medicine.

Second, the public health approach tends to stick to one particular test and not adapt to any new improvement in technology.  For years, the standard way of screening for vascular disease has been to measure blood cholesterol.  But now that we have heart scans, we know that blood cholesterol is a poor screening tests.  Well, it may take years for the public health authorities to figure that out and change their protocols, but a proactive doctor can stay on top of the new science and make better decisions in that respect.

Third, the public health approach finds value primarily if disease is detected but not so much if a bunch of tests come back normal.  But from the standpoint of the individual patient, you are going to value the screening procedure regardless of the test result.  If we detect a problem, then we’ve achieved one goal, which is to catch something in its early stages, but if the test comes back normal, that may be very reassuring to you and be of great value in bringing you piece of mind.

So for these three reasons, I think screening is a perfectly legitimate procedure that is worth considering, but to derive the most benefit it must be done thoughtfully and carefully one individual at a time.

I hope you have enjoyed this episode.  You will find the show notes on our blog page, and if you have any question pertaining to heart health you would like me to address, please go to the website, find the contact page and email it to me.

Thank you for joining me and happy holidays.