, Volume 29, Issue 9, pp 1218-1220
Date: 15 May 2014

Oversimplifying Overdiagnosis

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Estimating the frequency of overdiagnosis due to cancer screening is not a simple task, because overdiagnosis is almost never observable. Since we treat most cancers and their precursors, we rarely get to follow a tumor over its natural course and learn whether that tumor would have persisted as an indolent lesion, spontaneously regressed, or progressed to the point of producing symptoms.

To accurately assess the frequency of overdiagnosis, we need to really understand disease natural history. And this is a hard problem. In fact, one of the greatest controversies in the debate about overdiagnosis is how best to estimate this elusive quantity.

In this issue of JGIM, Zahl et al.1 comment on this controversy. To summarize, there are two main camps.2 One recognizes that overdiagnosis is a result of disease natural history that cannot be observed. Therefore, this camp uses statistical models to infer the most plausible underlying natural history. In a sense, this work uses observed data to ma ...