Comparison of the morphologic criteria (RECIST) and metabolic criteria (EORTC and PERCIST) in tumor response assessments: a pooled analysis

BACKGROUND/AIMS: 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. METHODS: Electronic databases were searched for eligible articles with the terms “RECIST,” “PERCIST,” or “EORTC criteria.” The level of concordance in the tumor responses between the two criteria was estimated using κ statistics. RESULTS: A total of 216 patients were collected from eight studies comparing the RECIST and EORTC criteria. The agreement of tumor responses between the two criteria was moderate (κ = 0.447). Eighty-six patients (39.8%) showed disagreement: tumor response was upgraded in 70 patients and downgraded in 16 when adopting the EORTC criteria. The EORTC criteria significantly increased the overall response rate (53% vs. 28%, p < 0.0001). The agreement of tumor responses between the RECIST and PERCIST was deemed fair (κ = 0.389). Of 407 patients from nine studies, 181 (44.5%) showed a discrepancy: using the PERCIST, tumor response were upgraded in 151 patients and downgraded in 30. When adopting the PERCIST, the overall response rate was also significantly increased from 30% to 55% (p < 0.0001). CONCLUSIONS: This pooled analysis demonstrates that the concordance of tumor responses between the morphologic criteria and metabolic criteria is not excellent. When adopting the metabolic criteria instead of the RECIST, overall response rates were significantly increased.