Dr. Timothy Wilt, a member of the United States Preventive Services Task Force, stood in front of the American Urological Association audience and explained why the task force could not recommend that men undergo routine PSA screening. At most, he explained, the test had been shown to benefit one out of 1000 men. Meanwhile, the test would cause hundreds of men to experience anxiety, and scores of them to experience impotence and incontinence from unnecessary treatments.
Twenty minutes later, I stood behind the same podium and asked the audience members to raise their hands if they disagreed with the task force’s conclusion. Ninety percent expressed their skepticism. What happened in the time between Wilt’s presentation and mine reveals a great deal about why experts cannot agree whether screening tests, like the PSA in middle-age men or mammograms in 40-year-old women, bring more benefit than harm, and about what psychological forces impede our ability, as a society, to figure out what basic bundle of healthcare services all insurance companies ought to pay for.
Wilt’s presentation was a model of scientific clarity. He explained that only two randomized clinical trials were conducted with enough scientific rigor to provide useful estimates of whether the PSA test saves lives. One trial showed no benefit and the other revealed the one in 1000 number which the task force took as the best case scenario. Wilt was followed on stage by Ruth Etzioni, a biostatistician at the Fred Hutchinson Cancer Research Center in Seattle. Etzioni presented a statistical model suggesting that the PSA test benefited many more than one in 1000 men.