BOX 2-2
After the Storm: Expert Reviews of Mammography Screening Trials

Physicians Data Query (PDQ) January 2002

The PDQ is an independent panel of cancer experts that regularly reviews evidence on cancer and prepares information for the National Cancer Institute (NCI). The PDQ posts its reports on the NCI website, but is independent of the NCI and does not issue guidelines or make official recommendations. It supported Gotzsche and Olsen’s criticism of mammography and concluded that “screening for breast cancer does not affect overall mortality, and that the absolute benefit for breast cancer mortality appears to be small.”

International Agency for Research on Cancer of the WHO March 2002

The group, consisting of 24 experts from 11 countries, concluded that trials have provided sufficient evidence for the efficacy of mammography screening of women between 50 and 69 years. The reduction in mortality from breast cancer among women who chose to participate in screening programs was estimated to be about 35 percent. For women aged 40-49 years, there is only limited evidence for a reduction. The quality of the trials that were used to make these evaluations was carefully assessed. The working group found that the effectiveness of national screening programs varies due to differences in coverage of the female population, quality of mammography, treatment, and other factors. Organized screening programs are more effective in reducing the rate of death from breast cancer than sporadic screening of selected groups of women.

Global Summit on Mammographic Screening June 2002

In response to the uncertainty over the efficacy of breast screening, a Global Summit on Mammographic Screening was organized at the European Institute of Oncology in Milan. The Summit was planned in association with the WHO, European Commission, American Cancer Society, U.S. Centers for Disease Control and Prevention, American Italian Cancer Foundation, European Society for Medical Oncology, American Society of Clinical Oncology, and International Union Against Cancer.

The design and recent results from the seven randomized trials were presented and discussed in detail. Some of the criticisms put forward by Gotzsche and Olsen were discarded as being wrong; others had been addressed by new analyses and

Although the debate on the benefits of mammography focused on the validity of the first seven clinical screening trials, these are only part of the evidence. A series of studies conducted in community settings that are more comparable to actual clinical practice have supported the conclusions of those earlier clinical screening trials.27 Overall, the evidence indicates that



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