Towards evidence based radiation oncology: improving the design, analysis, and reporting of clinical outcome studies in radiotherapy.

Although a substantial number of randomized clinical trials (RCTs) with a radiotherapy component have been conducted over time, it turns out that many of the trials have serious methodological flaws. What is even more frustrating is the circumstance that many RCTs, in radiotherapy as well as in other medical fields, are so heterogeneous in their reporting, that it is virtually impossible to judge their quality and thereby to judge the reliability of their conclusions. Recently, a new set of guidelines for reporting of RCTs has been proposed. These CONSORT (Consolidation of Standards for Reporting Trials) guidelines have now been accepted by a large number of medical journals. The present review presents the background for the CONSORT guidelines. Substantial research has been done on the methodological quality of RCTs reported in the literature and some of this will be reviewed here. Specific areas discussed include definition of endpoints, Type I and II errors, use of confidence intervals rather than P-values, randomization procedures, multiple significance tests, the intention-to-treat principle, and publication bias. Special concerns in relation to the reporting of radiotherapy RCTs are discussed as well. The conclusion is that we need to improve the quality of RCTs in terms of their design, conduct, analysis and reporting. As a step in that direction, a new set of guidelines for reports on treatment outcome in Radiotherapy and Oncology are presented. These guidelines meet the minimum criteria for reporting of RCTs as stated in the CONSORT guidelines.