Alternative Estimates for the Likelihood That a Woman With Screen-Detected Breast Cancer Has Had Her “Life Saved” by That Screening

We welcome the method by Welch and Frankel¹ of estimating the probability (P) that a woman with a screen-detected cancer had her life saved by the screening program [P(life saved  screen-detected cancer diagnosis)]. When using this model, the estimated probability ranges from 2.5% to 24.0%; for women aged 50 years, the estimated probability is 13%. We were intrigued by this number, since this probability previously has been estimated to be 4.8%.² In his model, Keen² used 2 parameters: (1) an estimate of the absolute risk reduction of breast cancer mortality with mammography screening and (2) the cumulative incidence of screen-detected cancers.