Swedish Two-County Trial: Impact of Mammographic Screening on Breast Cancer Mortality during 3 Decades László Tabár, MD, et al. Radiology September 2011 260:3 658-663.
Those seeking to question the value of screening mammography point to a lack of available data demonstrating a mortality reduction in populations being screened. In this landmark study, Dr. Tabar and colleagues, under the auspices of the Swedish National Board of Health and Welfare, enrolled over 133,000 women in a screening program in two Swedish counties, and randomized them into screening and control groups. They then followed the groups for 29 years, and assessed mortality. They found that there was about a 30% reduction in breast cancer mortality in women invited to screening. They then computed that about 500 women would be needed to be screened for 7 years to prevent one breast cancer death. Both the nominating committee and selection committees for the 2012 Margulis award felt that this was an exemplary manuscript for the inaugural Margulis award. Long term follow-up, such as the 30-year follow-up in this study, is exceptionally difficult to do and is crucially important to demonstrate the benefit of screening examinations such as mammography. Most important, Tabar and colleagues showed that the majority of prevented cancer deaths would have occurred after the first ten years of follow-up. This has clear implications for even wider recognition of the health benefits of screening mammography.