Mass Mammography: The Time for Reappraisal

Abstract

Of the four randomized controlled trials of mass mammography completed to date, the New York HIP trial used obsolete technology and was not designed to assess mammography in the absence of physical examination; the Swedish Two-County trial had serious methodological flaws; the U.K. trial was incompletely documented but showed no significant benefit; and the Malmö trial, which was perfect in design and execution, showed no benefit.Paradoxicially, with each successive trial and an increasing sophistication of mammography, the benefit of screening was becoming not greater but less. This may be summarized by comparing the number of women who would have to be offered mammography for one breast cancer death prevented or postponed in the respective trials: 5,000 in the HIP trial, 13,000 in the Two-County trial, 18,000 in the U.K. trial, and 68,000 in the Malmä trial.The enthusiasts in favor of mass mammography have created an atmosphere of false optimism. They have not informed the public about the very small potential benefit nor about the risks associated with screening, especially the risks of false positive diagnoses and of unnecessary surgical operations. This is an unacceptable situation, and the ethical vacuum in which population screening takes place needs to be filled with guidelines to protect women who are “targeted” for screening.