US breast cancer mortality is consistent with European data

According to Autier and colleagues,1 little of the decline in the breast cancer death rate in northern Europe can be attributed to screening mammography. Similar concerns in the United States led its Preventive Services Task Force to endorse the elimination of routine screening in women younger than 50 and the reduction of screening from every year to every two years in older women.2 The recommendations were immediately attacked, particularly by vested mammography interest groups (the so called mammography war).3

The figure⇓ shows US data obtained through SEER*Stat4 compared with the data in the report by Autier and colleagues,1 data for Belgium and Flanders being combined and the mammography curves interpolated from original discontinuous data.

Top: Percentages of women participating in screening mammography in each country. Bottom: Change in national breast cancer mortality rate relative to country’s mean rate during 1980-5

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The decline in breast cancer mortality in the United States is similar to that in Europe, and all countries are much more similar to each other than the variation in the advent and extent of screening mammography from country to country, as interpreted by Autier and colleagues. Moreover, to the extent that the countries can be ranked in mortality reduction, the relative order is unrelated to the temporal introduction of screening mammography.

The additional data from the US and the composite analysis lend further support to the conclusion that treatment and not screening has been the primary reason for mortality reduction. Screening mammography seems not only to have had a minor role in the progress gained but also to have created the problem of overdiagnosis, societal (financial and resource) cost, and controversy that will continue until a more effective screening method replaces what we are struggling to use and increasingly have to defend.5