Understanding Overdiagnosis as a Consequence of Cancer Screening

Overdiagnosis represents a central concern regarding the potential harms of cancer screening. In a Special Article funded by the Agency for Healthcare Research and Quality, the authors focus on defining, estimating, and communicating with patients about this important but elusive concept. Overdiagnosis — defined as detection of histologically confirmed cancer through screening that would not otherwise have been diagnosed during a person's lifetime had screening not happened — is not the only harm that can result from cancer screening. False-positive results, which occur when a screening test erroneously suggests cancer is present (e.g., positive breast imaging results leading to a negative biopsy) may be confused with overdiagnosis.

Because …