Meta-analysis: methods, strengths, and weaknesses.

Meta-analysis is a systematic, quantitative approach to the combination of data from several clinical trials that address the same question. This analytic approach can help resolve questions that remain unclear from the results of individual trials. Meta-analysis is of particular interest in oncology because of the small differences in efficacy between therapeutic alternatives. The large number of patients included in meta-analyses permit small to moderate benefits of a treatment to be reliably detected and larger treatment benefits to be quantified more accurately. Despite these apparent benefits, the use of meta-analysis has met with a great deal of resistance and has generated much controversy in clinical journals. After a brief description of the basic methods of conducting meta-analyses, this article will explore both their advantages and disadvantages.