Melanoma Screening and Mortality

The incidence of melanoma has increased steadily, yet mortality has risen to a much lesser extent. This can be explained at least in part by the concept of "overdiagnosis," where lesions are diagnosed as cancers that would not have caused mortality even if they had not been removed. Overdiagnosis (which is not "misdiagnosis") occurs when there is a pool of asymptomatic lesions—and screening efforts to detect them (1). The rationale is to reduce mortality by removing lesions that would have progressed at an early, curable stage. If there is a large pool of nonprogressing lesions that are indistinguishable from those with potential to progress, then the apparent incidence of "cancer" will increase while mortality will be affected less or not at all. This situation exists not only in relation to melanoma but also to breast, thyroid, renal, prostate, and other cancers (1).

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