Study “guesstimated” how many cancers would have occurred without mammography screening

De Glas and colleagues' conclusions are incorrect, having adopted the faulty method used by Bleyer and Welch. 1 2 All authors incorrectly claimed massive overdiagnosis of breast cancer and failure to reduce the rate of advanced cancers. 3 4 Both papers rely on "guesstimating" how many cancers would have occurred without screening and falsely claim that the excess beyond their guesses would have never occurred.