Effect of population-based screening on breast cancer mortality

Although the wider scientifi c community has long embraced the benefi ts of population-based breast screening, there seems to be an active anti-screening campaign orchestrated in part by members of the Nordic Cochrane Centre. These contrary views are based on erroneous interpretation of data from cancer registries and peerreviewed articles. Their specifi c aim seems to be to support a pre-existing opposition to all forms of screening. These individuals, making claims of poor methods, selectively discount overwhelming scientifi c evidence from numerous randomised trials in diff erent countries that organised screening reduces breast cancer mortality. They claim that the signifi cant decrease in breast cancer mortality achieved by screening is due to improvements in treatment alone, discounting the benefi ts of early detection. If true, this would imply that breast cancer is an exception among adenocarcinomas in that early detection does not improve prog nosis—a claim contrary to the evidence. For women with breast cancer, early detection also results in improved quality of life from less extensive surgical treatment. Women with screen-detected breast cancer in the UK have half the mastectomy rate of women with symptomatic cancers— ie, 27% versus 53%. Organised, high-quality breast screening is an important public health initiative by numerous governments worldwide. These policies are based on robust and extensive analysis of individualised patient data from scientifi c trials, with particular attention paid to the balance of potential benefi ts and harms. To imply that such an international action is mass misrepresentation, or that screening is done for the benefi t of self-interested professionals, is as perverse as it is unjustifi ed. Comprehensive guidelines deal with the entire screening process. Organisations responsible for screening programmes regularly review published evidence on the eff ects of mammographic screening, and also contradictory interpretations. We consider the interpretation by Jorgensen, Keen, and Gotzsche, of the balance of benefi ts and harms to be scientifi cally unsound. Women would be better served by focusing eff orts on how best, and not whether, to provide breast screening. The signatories below, charged with provision and implementation of breast screening in many diff erent countries, remain convinced that the scientifi c foundation for populationbased, quality-assured, organised breast screening is one of the major accomplishments of the translation of clinical cancer research into public health practice. Early detection, in combination with appropriate treatment, signifi cantly lowers breast cancer mortality and improves the life quality of patients with the disease.