Persistent Untreated Screening-Detected Breast Cancer: An Argument Against Delaying Screening or Increasing the Interval Between Screenings

Among 479 untreated breast cancers detected on screening mammography, none spontaneously disappeared or regressed. An unknown percentage of these cancers represent overdiagnosis, but because all untreated screen-detected cancers were visible and suspicious for malignancy at next mammographic examination, delaying the onset of screening or increasing the interval between screenings should not reduce the frequency of overdiagnosis.