Pitfalls in RECIST Data Extraction for Clinical Trials: Beyond the Basics.

Response Evaluation Criteria in Solid Tumors (RECIST) is a standardized methodology for determining therapeutic response to anticancer therapy using changes in lesion appearance on imaging studies. Many radiologists are now using RECIST in their routine clinical workflow, as part of consultative arrangements, or within dedicated imaging core laboratories. Although basic RECIST methodology is well described in published articles and online resources, inexperienced readers may encounter difficulties with certain nuances and subtleties of RECIST. This article illustrates a set of pitfalls in RECIST assessment considered to be "beyond the basics." These pitfalls were uncovered during a quality improvement review of a recently established cancer imaging core laboratory staffed by radiologists with limited prior RECIST experience. Pitfalls are presented in four categories: (1) baseline selection of lesions, (2) reassessment of target lesions, (3) reassessment of nontarget lesions, and (4) identification of new lesions. Educational and operational strategies for addressing these pitfalls are suggested. Attention to these pitfalls and strategies may improve the overall quality of RECIST assessments performed by radiologists.