Do the benefits of screening mammography outweigh the harms of overdiagnosis and unnecessary treatment?

To the Editor: Although both sides of the debate about screening mammography1,2 acknowledge the mortality benefit due to screening and the risk of overdiagnosis, the magnitude and relative value of these need further clarification and reflection. In calculating the number of breast cancer deaths averted using a relative risk reduction of 35%, Roder and Olver overstate the benefit. Other estimates of effect are lower (eg, 15%,3 16% [all ages] and 22% [> 50 years],4 and 19%5) and lead to a calculation of fewer averted deaths.