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Evidence Assessment for PDQ® Cancer Information for Health Professionals

The guiding principle of the editorial process for the PDQ health professional cancer information summaries is that evidence, linked to an evaluation of the quality of the evidence, takes precedence over a consensus of current practice. To develop and maintain the PDQ cancer information summaries, the PDQ Editorial Boards use an ongoing, systematic method for assessing the published literature related to the use of cancer-related interventions. To aid in these evaluations, the Editorial Boards use formal criteria to classify, or rank, the strength of the evidence from published research studies.

The Editorial Boards seek out the strongest published evidence available.

  • Reports of randomized controlled clinical trials and meta-analyses of randomized controlled clinical trials are used whenever possible.
  • Other study designs, such as non-randomized trials, cohort studies, and case series, will be considered for rare cancers and in cases where randomized controlled trials are not available, or instances where the literature on a topic is sparse.
  • Case reports are rarely considered.

In some cases, the description of the results in the PDQ cancer information summary is accompanied by cautionary statements about the limited strength and potential biases of the reported evidence.

Listed below are links to detailed descriptions of the criteria used by each PDQ Editorial Board to evaluate published studies: