The Two-County breast screening trial cannot provide a reliable estimate of the effect of breast cancer screening.

摘要

The estimated mortality reduction in the 29-year update of the Two-County trial by Tabar and colleagues, which appeared in the September 2011 issue of Radiology (1), is high-30%-but is inconsistent with that in trials of better methodological quality (2). Furthermore, the introduction of adjuvant therapies has fundamentally changed the premise of screening mammography, compromising the trial's validity in today's setting; however, this was not addressed (1).