The Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST) or European Organization for Research and Treatment of Cancer (EORTC) criteria are used to assess metabolic tumor responses. However, tumor responses have shown considerable discrepancies between the morphologic criteria (Response Evaluation Criteria in Solid Tumors [RECIST]) and metabolic criteria. We performed this pooled study to compare the RECIST and metabolic criteria in the assessment of tumor responses.