PDF of In the News 0610

Substantial incidence of cancer overdiagnosis indicates a need for the development of clinical and research strategies to avoid unnecessary treatment and other harms, according to a review published in the Journal of the National Cancer Institute (2010;102(9):605-613). Using data obtained from large ran­dom­ized screening trials, researchers learned that about 25% of the breast cancers detected on mammograms and about 60% of the prostate cancers detected with prostate-specific antigen (PSA) testing could represent overdiagnosis. Further findings revealed that 50% of the cancers detected in a lung cancer screening trial utilizing chest radiographs and sputum testing may have represented overdiagnosis.

The authors explained that in addition to screening, other procedures, such as diagnostic imaging, may contribute to overdiagnosis. An example of such diagnostic imaging is virtual colonoscopy, which often detects extracolonic abnormalities that can lead to more tests and possibly overdiagnsis.

In response to their findings, the study’s authors suggested strategies to help quantify, recognize, and manage overdiagnosis in cancer. One strategy would involve educating patients on the risks and benefits involved with early detection. “Whereas early detection may well help some, it undoubtedly hurts others,” the authors wrote. “Often the decision about whether or not to pursue early cancer detection involves a delicate balance between benefits and harms…. [D]ifferent individuals, even in the same situation, might reasonably make different choices.”

Offered as another strategy to help reduce cancer overdiagnosis, researchers suggested conducting studies that could raise the threshold at which a screening test result is labeled abnormal or when further steps should be taken. ONA