Benefit and risk of mammography screening: considerations from an epidemiological viewpoint

Abstract

Introduction: An organized mammography screening program is being implemented in Germany since the end of 2005. Even before its inception, a heated debate surrounded the question of how to communicate its rationale appropriately.

Methods: Selective literature review identifying facts relevant to informing decision making about mammography attendance.

Results: Decision making about individual attendance for mammography screening is crucially dependent on the reduction of risk of death from breast cancer for a diseased woman. This can be communicated in the following way: out of 100 women with a diagnosis of breast cancer 31 will die within the following 10 years without screening and 20 with screening (35% fewer).

Discussion: The actuarial concept of risk is defined by the probability of the undesired event multiplied by the expected magnitude of loss. This approach appears more appropriate for the appraisal of risk in the context of mammography screening than a pure event probability. It could help understand why women attend screening even if they perceive the risk of getting breast cancer as low--namely, that they rank the consequences of getting the disease as highly significant for themselves and others in their social environment.

Keywords: breast cancer; early detection; epidemiology; quality assurance; randomized studies; screening; survival time.