A public survey conducted in Europe found that the vast majority of people overestimate the life-saving benefits of breast and prostate cancer screening, according to a new study published online Aug. 12 in the Journal of the National Cancer Institute.
Gerd Gigerenzer, MD, director of the Center for Adaptive Behavior and Cognition at the Max Planck Institute for Human Development in Berlin, and colleagues conducted a survey of more than 10,200 people from nine European countries (Austria, France, Germany, Italy, the Netherlands, Poland, Russia, Spain and the United Kingdom) to assess perceptions of cancer-specific mortality reduction associated with mammography and prostate-specific antigen screening and to determine the sources of information upon which they rely.
The researchers found that the majority of participants (aged 50-69 years) have a dramatic overestimation of the benefits of such tests, and that doctors and other sources of information appear to have little impact on improving knowledge of the level of benefit.
Specifically, the authors wrote that 92 percent of women overestimated the benefit of mammography screening by at least one order of magnitude or reported they did not know; 89 percent of men overestimated the benefit of prostate-specific antigen screening or did not know.
They also found that frequent consultation of sources of medical information (including physicians) was not associated with more realistic knowledge of the benefits of screening.
"Knowing the benefit of a treatment is a necessary condition for informed consent and rational decision making," Gigerenzer and colleagues wrote. The authors also concluded that in the countries investigated, physicians and other information sources appear to have little impact on improving citizens' perceptions of these benefits.
In an accompanying editorial, Lisa M. Schwartz, MD, and Steven Woloshin, MD, of the Dartmouth Institute for Health Policy & Clinical Practice in Hanover, N.H., pointed out that accurate screening messages should be more prominent and include risks associated with over-diagnosis and over-treatment.
However, Schwartz and Woloshin called some of the researchers' methods biased toward overestimation and question if participants are truly representative of the European Union, but also acknowledged the study's contribution. "These cautions...do not diminish the importance of the study," they wrote. "We need to move from selling screening to helping people realize that screening is a genuine choice."