title: Meta-analyses of randomised clinical trials in oncology.
abstract: A meta-analysis is a quantitative synthesis of randomised clinical trials, used to evaluate moderate treatment effects in oncology. It is complementary to large-scale trials. We describes the principles, methods, and limits of meta-analyses. The gold standard for a meta-analysis is to obtain individual patient data directly from each principal investigator, but this is time-consuming and costly. The main steps of a meta-analysis using individual patient data are described. Multidisciplinary collaboration is needed for clinical insight and critical review of the data and results. Meta-analysis should include an evaluation of the trial quality, a quantification of the overall treatment effect, a study of the variations seen in this effect between trials, and pre-planned exploratory analyses to identify groups of patients who may benefit more from the treatment. Statistical methods are explained using real working examples. Since literature-based meta-analysis can lead to seriously biased assessments, meta-analyses of individual patient data should be undertaken systematically when long-term follow-up is needed, when a detailed analysis is important, or when the literature-based meta-analyses are not in agreement. The main factors which influence the quality of a meta-analysis are discussed.
authors.affiliation: Biostatistics and Epidemiology Unit, Institut Gustave-Roussy, Villejuif, France. jppignon@igr.fr
authors.forename: J P
authors.initials: JP
authors.lastname: Pignon
authors.forename: C
authors.initials: C
authors.lastname: Hill
mesh_terms: D003627:Data Interpretation, Statistical; D005544:Forecasting; D006801:Humans; D015201:Meta-Analysis as Topic; D009369:Neoplasms / Q000628:therapy*; D016032:Randomized Controlled Trials as Topic / Q000592:standards