CBS promotes “essential/critical” screening tests but never mentions over-diagnosis

The following is a guest blog post by Alan Cassels, 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). The opinions are his; you are welcome to your own.


While the Beatles might have famously sang that “All you need is love”, according to CBS News, you may also need other stuff, like medical screening tests.  Critical…essential screening tests CBS called them.

We media consumers who are living our lives naïvely unaware of impending medical problems, will learn very little from this CBS two-part series on medical screening   “The routine screening tests critical to women’s health”  (Feb. 16) and “The routine screening tests essential to men’s health (Feb 18) except that there are a battery of lifesaving tests that we allegedly need to do to keep healthy.  In two short videos, and accompanying text, these articles are listicles, portraying many screening tests as necessary, vital, lifesaving and without any downsides.    This is an uninformative message to leave with the viewers.

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 strong belief up front:  In any story about medical screening, (which is looking for signs of disease in otherwise healthy people), if the story doesn’t mention the concept of overdiagnosis either directly or indirectly, then that story has a fatal flaw.   Why?  Because all screening tests involve some degree of overdiagnosis and this means people will be harmed.

Sadly this pair of CBS stories conspicuously never broaches the subject of overdiagnosis (a topic so vital that entire conferences are now dedicated to examine ways to prevent it – CBS should attend and report on one of these events), though they did briefly outline that for many people current screening recommendations are confusing.  The story on women’s required screening tests tells us that “mammograms, pap smears and colonoscopies have the potential to save millions of lives. But many women still don’t know when they’re supposed to start getting them or how often the tests are really needed.”

Clearly there’s confusion, but boy, isn’t that a great subject for a story?   Why is the public so confused about recommendations around screening?  Clearly anyone watching how prostate and breast cancer screening recommendations have been trending over the last few years 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. That is, 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 disagreements over how effective or safe medical screening tests are.

Some groups used to call for more prostate cancer screening and more breast cancer screening more often and starting at earlier ages than what is generally recommended today.  Why?  Because better research is capturing the problem of overdiagnosis, alerting us to the many issues related to false positive and false negative findings, and reminding us that there is a 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 says 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.

What about talking about the sources of confusion around screening recommendations?  Isn’t it of keen interest to the viewers that the most reliable committee on screening in the US, the United States Preventive Services Task Force produces guidelines on mammography recommending women start regular screening at age 50 and do it every two years till age 74 but the American Cancer Society says women should get a mammogram every year starting at 40 “and continuing as long as a woman is in good health.”

One group recommends screening twice as often as another group?  Does this have anything to do with the independent, science-based orientation of one group (the USPSTF) versus the advocacy, fundraising and professionally-invested positioning of the other (the ACS)?   CBS’s two-part report could have touched on the professional and financial conflicts of interest that are inherent in any medical enterprise and inform the viewer that there are valid reasons why not all recommendations are equally reliable.

For men, the fact that the many controversies over PSA testing are never broached in this story was a missed opportunity.  The report notes that “PSA guidelines recommend against screening for prostate cancer, but some doctors recommend getting a baseline test at age 40.”   What it didn’t say that 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 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 as the “Poster Child for Overdiagnosis.”  I described prostate screening in a previous blog post, saying that 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 what Dr. David Sackett called 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.


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Comments (12)

Please note, comments are no longer published through this website. All previously made comments are still archived and available for viewing through select posts.

Tazia K. Stagg

February 20, 2015 at 10:40 am

Alan, preventive medicine certainly has some significant problems, but I disagree with the claim that it is arrogant.

Tazia K. Stagg

February 20, 2015 at 11:08 am

I think what you and Dr. Sackett meant to say was that spreading inaccurate information about prevention is wrong and cruel. Legitimate preventive medicine experts do exist, and you didn’t mean to attack us, right?

Alan Cassels

February 20, 2015 at 11:55 am

Thank you for the comments. I think we’d both agree that legitimate preventive medicine does exist and it is supported by good evidence and accurate information. I don’t think Sackett would say all of preventive medicine is arrogant either.
If I listen closely to my inner pit bull this is what he is growling: Many widely promoted screening programs have been launched, capturing millions of people in their nets, without having a clue on how much harm they could be inflicting. Dr. Gilbert Welch estimates there are 2 million American men who have been treated for prostate cancer that never would have gone on to hurt them, and hundreds of thousands of those now wear diapers and can’t have sex. Those men had a PSA test because someone promised it would save their lives. Let me put a question back to you: how can we ever be absolutely sure we are helping and not hurting people by asking them to submit to preventive screening tests?

Tazia K. Stagg

February 20, 2015 at 3:28 pm

If I answer well, will you retract the insult?

Catherine Oliver

February 21, 2015 at 8:28 am

Preventive medicine as I think of it, comes in 3 parts: The most effective preventive medicine is public health interventions like clean water, poverty reduction. Second most effective is individual client interventions such as help to quit smoking or encouragement to exercise. And least effective is screening of well individuals for “early detection” which has turned out for most diseases to be a waste of resources.


February 21, 2015 at 11:39 am

Since the real facts, rather than the medical industry-funded flawed fabricated “scientific” studies, show that routine cancer screening tests do not notably reduce cancer mortality (see this study: “Does screening for disease save lives in asymptomatic adults? Systematic review of meta-analyses and randomized trials”) and potentially cause more harm than good such as with mammography (see Peter Gotzsche’s ‘Mammography Screening: Truth, Lies and Controversy’ and Rolf Hefti’s ‘The Mammogram Myth’ – more on that at TheMammogramMyth dot com), the correct conclusion is that it is more critical for women’s health NOT to have most routine screening tests.

Tazia K. Stagg

February 21, 2015 at 2:06 pm

Let’s not oversimplify.

Tazia K. Stagg

February 22, 2015 at 7:14 am

This piece could lead readers to believe:
• The coverage cited would be all better if only it had thoroughly discussed overdiagnosis.
• Preventive medicine is arrogant (because CBS, urologists, and others practice it poorly).
• People don’t need screening tests, they just need information about screening tests.

Gary Schwitzer

February 22, 2015 at 5:22 pm

A story late last week: Mammogram Rates May Fall When Women Learn of ‘Overdiagnosis’ Risk –

Daniel Pendick

February 23, 2015 at 9:23 am

Dr. Cassels,

I applaud any effort to reign in overdiagnosis and overtreatment, which is way past epidemic in the US. But overstating the case, or misrepresenting the work being critiqued, does no one any good. You say this, for example:

“In any story about medical screening, (which is looking for signs of disease in otherwise healthy people), if the story doesn’t mention the concept of “overdiagnosis” either directly or indirectly, then that story has a fatal flaw.”

I point you to this statement in the article in question:

“This is because patients who do not have prostate cancer may still have an elevated levels of this specific enzyme in the blood, leading to other invasive — and often unnecessary — tests. So doctors often are prudent when deciding which patients should have a PSA. However, some doctors recommend all male patients have a baseline PSA test at age 40.”

The writer is clearly acknowledging a major risk of PSA screening (downstream overtesting). No, it does not explicitly take on overdiagnosis, but it does communicate that having a PSA test is not without risks. Why not give credit where it is due?

Health writing is really hard, even when you are trying to do it right. Be fair.

    Tazia K. Stagg

    February 23, 2015 at 10:47 am

    Regardless of whether overdiagnosis is mentioned, promoting prostate cancer screening is unacceptable.

February 23, 2015 at 10:10 am

You’re absolutely right. Since these stories were about a large battery of tests, including colon, breast and lung cancer screening, and cholesterol and blood pressure checking, I would’ve liked to have seen the same sorts of caveats (risks of overdiagnosis) made about the “Poster Child” of overdiagnosis extended to those too. Thanks for pointing out where I should’ve given credit.