Cancer Experts Find Too Many People Are Being Screened, Diagnosed, and Treated for Disease
A recent commentary published in Annals of Internal Medicine discusses the paradoxical finding that most patients are at below-average risk of disease and can expect to experience less-than-average benefits from a treatment. Yet, argue Vickers et al, 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 belief the “Lake Wobegon effect,” after the fictional Midwestern town of Lake Wobegon where “all the women are strong, all the men are good looking, and all the children are above average.” Having a better understanding of the Lake Wobegon effect on patients will help physicians focus screening programs on patients who have the most to gain.
Study Methodology
The authors conducted and examined studies investigating such issues as the limitations of applying summary results of clinical trials to individual patients; personalized decision-making about potential benefits of lung cancer screening; whether primary angioplasty for some is as good as primary angioplasty for all; and the influence of blood prostate-specific antigen (PSA) levels at age 60 on benefits and harms of prostate cancer screening.
Discussion
In their article, the authors argue that prostate cancer is the perfect example of the Lake Wobegon effect and how it leads to overdiagnosis. They write that after the introduction of screening using the PSA test, mortality decreased slightly, but incidence and treatment increased dramatically.
“We believe that typical approaches to prostate cancer screening, which assume that all men are at average risk, are a major cause of overdiagnosis,” wrote the study authors. “In fact, risk can be very strongly separated depending on PSA levels. Men in the top quartile of PSA levels at age 60 years (≥ 2 ng/mL) have a 20-times greater risk for prostate cancer death than do those with lower PSA levels, and 90% of deaths by age 85 years occur in this group—a clear example of the Lake Wobegon effect. We recently showed that screening only men at high risk rather than screening all men drastically reduced screening harms, in terms of overdiagnosis, but retained 100% of the screening benefits, in terms of mortality reductions, because screening did not reduce prostate cancer deaths in the group with low PSA levels.”
The Lake Wobegon effect is a common and underappreciated phenomenon in medicine with important clinical implications, said the authors. “A better understanding of this effect, and a better use of risk prediction in both research and clinical practice, will be essential to ensure that we focus our attention on patients who stand the most to gain,” they concluded.
Andrew Vickers, PhD, Attending Research Methodologist at Memorial Sloan Kettering Cancer Center, is the corresponding author of the Annals of Internal Medicine report.
Funding for this article was provided by the Prostate Cancer Foundation, the Sidney Kimmel Center for Prostate and Urologic Cancers, and the National Cancer Institute.
Dr. Vickers is on the advisory board of Opko Health, Inc, and a consultant for Genomic Health and Genome DX.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
