Cancer screening is plagued by dissonance

Cancer screening is plagued by dissonanceLast year, the USPSTF was poised to meet regarding its prostate cancer screening guidelines.

According the Kenny Lin, a physician who was with the Task Force at the time, the meeting was cancelled for political reasons. He points us to a New York Times story on the dueling narratives of prostate cancer screening.

It’s a topic that often appears here on KevinMD.com, and it seems to have endless life.

On one side are the specialty-based recommendations that support PSA screening, backed by emotional anecdotes from prostate cancer survivors.

On the other are the evidence-based recommendations, like the ones from the USPSTF. As the Times story notes, this camp “makes a less emotionally satisfying argument: on balance, scientific studies do not support the claim that screening healthy men saves lives. Screening … can lead healthy men into a cascade of further testing and treatments that end up injuring or even killing them.”

This is a familiar dissonance that plagues the cancer screening debate.

Cancer screening is generally presented only in a positive light in mainstream media. “Early detection saves lives,” is what we often hear. But the reality is more nuanced, and unfortunately, isn’t prone to pat soundbites or inspirational ad campaigns.

Consider the following metaphor that illustrates this phenomenon, starkly told by David Newman, a director of clinical research at Mount Sinai School of Medicine in Manhattan:

“Imagine you are one of 100 men in a room,” [Newman] says. “Seventeen of you will be diagnosed with prostate cancer, and three are destined to die from it. But nobody knows which ones.” Now imagine there is a man wearing a white coat on the other side of the door. In his hand are 17 pills, one of which will save the life of one of the men with prostate cancer. “You’d probably want to invite him into the room to deliver the pill, wouldn’t you?” Newman says.

Statistics for the effects of P.S.A. testing are often represented this way — only in terms of possible benefit. But Newman says that to completely convey the P.S.A. screening story, you have to extend the metaphor. After handing out the pills, the man in the white coat randomly shoots one of the 17 men dead. Then he shoots 10 more in the groin, leaving them impotent or incontinent.

Newman pauses. “Now would you open that door?” He argues that the only way to measure any screening test or treatment accurately is to examine overall mortality. That means researchers must look not just at the number of deaths from the disease but also at the number of deaths caused by treatment.

The potential risks of cancer screening needs to be presented in the same light as its benefits. That includes the possibility of harm from increasingly invasive testing, along with complications from treatment.

Only when this complete picture is presented in the media can patients make a better informed decision.

 is an internal medicine physician and on the Board of Contributors at USA Today.  He is founder and editor of KevinMD.com, also on FacebookTwitterGoogle+, and LinkedIn.

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