Wednesday, October 5, 2011

The politics of medical recommendations

Despite the seeming logic of the P.S.A. test, the evidence that it saves lives is far from conclusive, and [chief medical and scientific officer of the American Cancer Society Otis Webb] Brawley is not the only one questioning it. A growing cadre of doctors, epidemiologists, patients and cancer biologists are rethinking its value. And the most recent studies, while not ending the debate, indicate that routine P.S.A. testing appears not to reduce the number of deaths, and if it does, the benefit is exceedingly modest. ...

So what should a man do when his doctor suggests a routine P.S.A. test? The U.S. Preventive Services Task Force, a panel of independent experts that evaluates the latest scientific evidence on preventive tests and treatments, is charged with making recommendations in just such situations. ... According to an internal document, in 2009 the task force conducted an in-depth analysis of data and seemed poised to give routine P.S.A. testing a “D” rating — “D” as in don’t do it — for any man of any age. But this was around the time that the task force stated that routine mammography for women ages 40 to 50 was not necessary for every woman. That recommendation caused a public uproar, and Ned Calonge, the task-force chairman at the time, sent the P.S.A. recommendation back for review. One year later, in November 2010, just before midterm elections, the task force was again set to review its recommendation when Calonge canceled the meeting. He says that word leaked out that if the November meeting was held, it could jeopardize the task force’s financing. Kenneth Lin, the researcher who led the review, quit his job in protest, and now, nearly two years after its initial finding, it remains uncertain when the task force will release its rating for P.S.A. screening. ...

David Newman, a director of clinical research at Mount Sinai School of Medicine in Manhattan, looks at it differently and offers a metaphor to illustrate the conundrum posed by P.S.A. screening.

“Imagine you are one of 100 men in a room,” he 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?”
--Shannon Brownlee and Jeanne Lenzer, NYT Magazine, on the dirty business of medical task forces