Thursday, November 8, 2012

The Risks of Medical Screening Tests

The following information was abstracted from an article in the most recent edition of The New England Journal of Medicine, one of the most respected medical journals in the world.  It is an article discussing cancer screening campaigns.

The article describes how various medical organizations use the art of persuasion to call the public's attention to the "value" of cancer screening techniques, e.g. mammograms, colonoscopy, etc.  These campaigns are designed to "make people feel vulnerable and then offer them hope, by often framing statistics "to provoke alarm," and then "exaggerating the benefit (and ignoring or minimizing the harms.)"

Example:  "If you're a woman over 35, be sure to schedule a mammogram.  Unless you're still not convinced of its importance.  In which case you may need more than your breasts examined......."  This was a persuasive technique used by the American Cancer Society, but since abandoned.  However, Memorial Sloan-Kettering Cancer Center recently ran an ad in the New York Times that read "The early warning signs of colon cancer:  You feel great.  You have a healthy appetite.  You're only 50."  Scary, no?  Well, the article points out, the vast majority of the readers of this ad who have the "non-symptoms" described are actually totally well and will not have, nor soon develop, colon cancer.  Such an individual's risk of dying from colon cancer is 0.2%!  No complications of the procedure, such as colon perforation or secondary bleeding are described.

The Journal goes on to point out that research has shown that screening can clearly cause harm.  Anxiety, as well as additional complications from the continued unnecessary evaluation of false positive findings are some of the drawbacks, not to mention "over diagnosed cancers" - those never destined to cause symptoms or death.

The National Cancer Institute is developing an improved guide for patients, so that they may better evaluate the risks v. the benefits of particular screening techniques.

Statistics are very important in decision making, especially where your health is concerned.  Realize that almost no screening test is without some inherent risk and can be quite costly.  Be sure the test has been found to be truly beneficial before proceeding.

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