The American Society of Clinical Oncology (ASCO) guidelines program employs a systematic review–based methodology to produce evidence-based guidelines. This is consistent with the stance of the Institute of Medicine on guideline development, which is that high-quality evidence syntheses form the basis for recommendation development.
In the absence of high-quality evidence, recommendation development becomes more complex. One option is to provide no recommendations or withdraw a guideline topic. However, it is often the areas of greatest uncertainty in which the evidentiary base is incomplete, and thus, guidelines are needed most. To provide recommendations in such circumstances, an explicit methodology is needed to ensure that a credible process is undertaken, and rigorous, reliable advice is provided.
In 2010, the ASCO Board of Directors approved development of guideline recommendations using consensus methodology. A modified Delphi approach to recommendation development, based on the best available data identified in a systematic review, was piloted with an ASCO guideline. Consensus was achieved through the rating of a series of recommendations by a large group of clinicians, including academic and community-based content and methodology experts. A prespecified threshold of agreement was determined to indicate when consensus was achieved. Consensus was defined as agreement by ≥ 75% of raters.
The formal consensus methodology used by ASCO enabled development of guideline recommendations on a challenging clinical issue based on limited evidence using a rigorous, transparent, and explicit method. This methodology is proposed for development of future ASCO guidelines on topics for which limited evidence is available.