All the Tests You Need (but who do you trust around your “needs”?)
 by Alan Cassels • Canada

While the Beatles might have famously sang that “All you need is Love,” according to many medical experts you may also need other stuff, like medical screening tests.

We media consumers who are living our lives naïvely unaware of impending medical problems, will learn very little from those who are promoting medical screening tests. A lot of the time the promoters of these tests portray them as necessary, vital, lifesaving and without any downsides. This is an uninformed message to leave with the general public.

We should welcome good journalistic reporting of medical screening recommendations especially given the “better safe than sorry” culture in which we are all swimming. Let me, however, state my elephant-sized bias up front: In any promotional information about medical screening, (which is looking for signs of disease in otherwise healthy people), if the information doesn’t mention the concept of “over-diagnosis” either directly or indirectly, then that story has a fatal flaw. Why? Because all screening tests involve some degree of over-diagnosis and this means people will be harmed.

If you have been, like me, watching how prostate and breast cancer screening recommendations have been trending over the last few years, you will know that the two most well-studied and evidence-based forms of screening on the planet have recommendations that are moving targets and they all seem to move in the same direction: more conservative, i.e. what was recommended last year or even last month may not be recommended today. These shifting sands are the terrain that any good reporting on medical screening has to navigate because new evidence emerges constantly, often revealing vast discrepancies over how effective or safe medical screening tests are.

Officials used to say every man over 40 needed a PSA test and every woman over 35 required an annual mammogram, but neither of those things hold true today. Why? Because better research is capturing the problem of over-diagnosis, alerting us to the many issues related to false positive and false negative findings, and reminding us that there is always the potential for harm, both psychological and physical. Despite the marketing of breast cancer screening’s lifesaving potential, most people don’t know that the yield is very low. The best systematic evidence from the Cochrane Collaboration says that you have to screen about 2,000 women for ten years to save one woman dying of breast cancer, yet you will cause about 200 women to undergo psychological distress and ten will be treated unnecessarily.

Since mammography is such a widely promoted and divisive enterprise, any journalistic treatment of it that fails to mention high quality evidence of benefit and harm deserves a public spanking.

For men, the fact that the many controversies over PSA testing are never broached in this story was a missed opportunity. The report notes “PSA guidelines recommend against screening for prostate cancer, but some doctors recommend getting a baseline test at age 40.” What it didn’t say is that if you consulted the most unbiased and authoritative source on PSA screening (the USPSTF), you would have found they give the big thumbs down to baseline bafflegab and simply say don’t routinely offer PSA tests for healthy men. The reasons are straightforward as the PSA test has left hundreds of thousands of men impotent, incontinent or both due to the treatment, with very few lives saved. Others have awarded it the title “Poster Child for Overdiagnosis.” Let’s be clear: the PSA test is a simple blood test that unleashes a cascade of interventions, worry and medical activity.

Each of the screening tests mentioned, including those for breast, cervical and colon cancer, blood pressure, glucose and cholesterol also fail to discuss any downsides for which there are many. And don’t get me going why those guidelines are all over the map with some groups recommending never testing cholesterol, to others recommending it be checked almost in utero. The suggestion that otherwise healthy people need to be constantly, proactively probed and scanned for impending disease, without the discussion of the benefits and harms represents the arrogance of preventive medicine, which often comes across as aggressively assertive, presumptive, and overbearing. I would politely ask any media outlet to take things to the next level on screening by challenging this arrogance instead of promoting it.

Bottom line for me: people do “need” something, perhaps in addition to love. They need high quality information about medical screening. They need to know there are perfectly good reasons why screening is controversial and recommendations clash. They need to know that harm can mount when screening recommendations are made for too wide and too unselective an audience.

Alan Cassels is a pharmaceutical policy researcher at the University of Victoria and the author of Seeking Sickness: Medical Screening and the Misguided Hunt for Disease (Greystone, ©2012).