The impact of clinical practice guidelines and clinical trials on treatment decisions.

With increasing numbers of clinical practice guidelines (CPGs) becoming available to guide physicians, it is important to understand how guidelines are developed. Of importance, is evaluation of the scientific evidence on which guidelines are based, indeed whether the guideline is evidence based or based on expert opinion alone. This report will review in general, guideline development. The impact of CPGs, including expected outcomes, as well as potential harms is discussed. Clinical trials, meta analyses and CPGs relevant to the treatment of lung cancer are reviewed.