Are advancements in screening technology contributing to breast cancer over-diagnosis?

Advancements in breast screening technology have increased the sensitivity of screening and thereby increased the detection rates of nonlethal cancers. Thus, improvements in breast screening technology may contribute to 'over-diagnosis', which refers to detection of cancers that pose no threat to life and that, in the absence of screening, might never have been detected. The purpose of this review is to draw attention to risks of over-diagnosis and provide a rationale for evaluating screening clinical breast examination (CBE) as an alternative to modern technology-based (mammography) screening.

Novel screening technologies have been adopted largely on the basis of their abilities to increase tumor-detection rates. However, as breast cancer treatments have improved, the mortality benefits of screening have declined. Moreover, there is evidence suggesting that, in the modern era of effective adjuvant systemic therapies, the mortality benefit of screening CBE may now be comparable to that of modern screening mammography, but screening CBE carries less risk of over-diagnosis.

A randomized trial comparing modern mammography screening versus screening CBE is warranted. If confirmed that the mortality benefits of the two screening strategies are now comparable, then screening CBE might be considered a reasonable alternative to mammography screening.