Cancer experts from Memorial Sloan Kettering Cancer Center in New York and Tufts Medical Center in Boston, write that too many people are being screened, diagnosed, and treated for disease because they mistakenly believe they are at higher risk than they actually are. The authors call this the "Lake Wobegon Effect" after the fictional Midwestern town of above-average citizens featured in Garrison Keillor's A prairie Home Companion. Their commentary is published in Annals of Internal Medicine.
The authors argue that prostate cancer is a perfect example of the Lake Wobegon Effect and how it leads to overdiagnosis. Prostate cancer screening programs assume that all men are at average risk, when risk can be very strongly separated depending on PSA levels. For example, men in the top quartile of PSA levels at age 60 have a 20-times greater risk for prostate cancer death than those with lower PSA levels. Screening only men at high risk, rather than screening all men, drastically reduces screening harms in terms of overdiagnosis, but retains 100 percent of the screening benefits in terms of mortality reductions. The authors suggest that having a better understanding of the Lake Wobegon Effect will help physicians focus screening programs on patients who have the most to gain.