18 19 Although few studies have been based on bayesian updating for elucidating the relative contribution of mammography screening to the decline in mortality, 20 21 none was primarily designed for estimating overdiagnosis.
The role of mammography screening in these declines is much debated.
Although the mortality reduction is currently believed (even from screening supporters) to be about half of the initially claimed 30-35% [ 20– 22], the contribution of mammography screening to the general mortality decline has often been considered substantial [ 23, 7].
1 Despite upward trends in incidence rates, due to an increasing exposure to risk factors and widespread use of mammography screening, 2 mortality has been declining in most affluent settings, 3 reflecting improvements in access to earlier diagnosis and effective treatments.
33 We did not, however, see similar declines in the countries we examined, and the declining use of mammography screening in the United States has also been suggested as an explanation.
Some experts credit mammography screening for up to half the decline; others credit it less, or not at all.
Recent published reports have shown a decline in the mammography screening rate in women over age 40, but it is not known whether this trend is a reason for concern in the Medicare population.
Mainstream breast cancer organizations continue to focus on screening as the primary tool to address the breast cancer epidemic, despite the fact that mammography screening programs have not produced a significant decline in death rates.
Experience with mammography screening has shown that, with frequent testing, adherence may decline over time (68).
The decline in breast cancer mortality has been largely attributed to regular mammography screening practice [ 12].
