Public Knowledge of Benefits of Breast and Prostate Cancer Screening in Europe

Gerd Gigerenzer, Jutta Mata, Ronald Frank

Affiliations of authors: Harding Center for Risk Literacy, Max Planck Institute for Human Development, Berlin, Germany (GG); Faculty of Human Kinetics, Technical University Lisbon, Lisbon, Portugal (JM); Gesellschaft für Konsumforschung Association, Nuremberg, Germany (RF)

Correspondence to: Gerd Gigerenzer, PhD, Harding Center for Risk Literacy, Max Planck Institute of Human Development, Lentzeallee 94, 14195 Berlin, Germany (e-mail: gigerenzer@mpib-berlin.mpg.de).

Making informed decisions about breast and prostate cancer screening requires knowledge of its benefits. However, country-specific information on public knowledge of the benefits of screening is lacking. Face-to-face computer-assisted personal interviews were conducted with 10 228 persons selected by a representative quota method in 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 (PSA) screening. Participants were also queried on the extent to which they consulted 14 different sources of health information. Correlation coefficients between frequency of use of particular sources and the accuracy of estimates of screening benefit were calculated. Ninety-two percent of women overestimated the mortality reduction from mammography screening by at least one order of magnitude or reported that they did not know. Eighty-nine percent of men overestimated the benefits of PSA screening by a similar extent or did not know. Women and men aged 50–69 years, and thus targeted by screening programs, were not substantially better informed about the benefits of mammography and PSA screening, respectively, than men and women overall. Frequent consulting of physicians (r = .07, 95% confidence interval [CI] = 0.05 to 0.09) and health pamphlets (r = .06, 95% CI = 0.04 to 0.08) tended to increase rather than reduce overestimation. The vast majority of citizens in nine European countries systematically overestimate the benefits of mammography and PSA screening. In the countries investigated, physicians and other information sources appear to have little impact on improving citizens’ perceptions of these benefits.


CONTEXT AND CAVEATS

Prior knowledge

Given the harms that can ensue from cancer screening procedures, people’s decisions as to whether to undergo cancer screening should be based on a realistic knowledge of its benefits.

Study design

Face-to-face-interviews were conducted among a representative sample of men and women in nine European countries, who were asked to choose among estimates of the number of fewer cancer-specific deaths (per 1000 individuals screened) by prostate-specific antigen and mammography screening, respectively. Participants were also queried as to their sources of medical information.

Contribution

This study found dramatic (by an order of magnitude or more) overestimation of the benefits (absolute cancer-specific mortality reduction) of mammography and prostate-specific antigen testing in the vast majority of women and men, respectively, in all countries surveyed. Frequent consultation of sources of medical information (including physicians) was not associated with more realistic knowledge of the benefits of screening.

Implications

A basis for informed decisions by people about participation in screening for breast and prostate cancer is largely nonexistent in Europe, suggesting inadequacies in the information made available to the public.

Limitations

The influence of the public's overestimation of screening benefits on actual participation in screening was not addressed in this study, and the work was restricted to European countries.

From the Editors

Fore more details: http://jnci.oxfordjournals.org/cgi/content/abstract/djp237