Meta-analysis and prospective meta-analysis in childhood leukemia clinical research.

In this paper, we consider the role of meta-analysis and 'prospective meta-analysis' studies in childhood acute lymphocytic leukemia (ALL). In this issue, Valsecchi and Masera [1] give a thoughtful discourse, generally favorable to this approach. This article presents the opposite point of view. The aims of our article are to present the implications in clinical, rather than biostatistical terms, and to provide an extensive literature review of the subject of meta-analysis. We conclude that treatment assessments, resulting from meta-analysis of closed studies (retrospective) should be met with healthy skepticism. Trials requiring international resources should be true intergroup trials with a single coordinating center, rather than prospective meta-analysis, unless it is a question grafted onto each group's own research agenda. For example, each group might ask its own systemic control question, but a CNS protection question is asked collectively.