[Extending the limits of lymphadenectomy during radical cystectomy: pitfalls in the interpretation of contemporary study results].

The optimal extent of lymphadenectomy performed during radical cystectomy for transitional cell carcinoma of the bladder is currently under intensive debate. Extending the limits of lymphadenectomy has been hypothesized to add further diagnostic and therapeutic benefit. However, our current knowledge is based exclusively on results from retrospective studies that are hampered by several statistical shortcomings. This article provides a critical analysis of the contemporary data on the subject and outlines typical statistical pitfalls that must be considered when interpreting such research results.