Overdiagnosis of screen‐detected breast cancer

Screen‐detected breast cancer overdiagnosis occurs, but each woman has been diagnosed with cancer that cannot be ignored

There are an increasing number of publications estimating the extent of cancer overdiagnosis, which for breast cancer is in the context of population cancer screening programs.1 Researchers investigating overdiagnosis point to a range of related harms, but it is important to view these in the context of screening benefits, such as reductions in risk of breast cancer death.2 Care needs to be taken not to conflate formal screening programs with informal or opportunistic approaches to early detection, such as prostate‐specific antigen (PSA) testing in prostate cancer. This article focuses on the risk of overdiagnosis in the context of population‐based breast screening programs, given that overdiagnosis is often at the heart of calls to cease mammographic breast cancer screening.3,4 Despite the emphasis often given to breast cancer screening in discussions of overdiagnosis, the concept should not be regarded as only applying to breast cancer screening, or to cancer screening more generally, but as an outcome that could apply, to varying degrees, to a wider range of screening and diagnostic practices.