Predictive value of interim and post-treatment PET/CT for clinical evaluation in pediatric and adolescent Hodgkin lymphoma: A comparison of the Deauville Criteria and the International Harmonization Project Criteria

Background. The criteria for response evaluation in pediatric and adolescent Hodgkin lymphoma (HL) are controversial. We compared different criteria for the interpretation of interim and post-treatment PET/CT to predict the outcome of pediatric and adolescent HL. Procedure. Baseline, interim, and post-treatment 18F-FDG-PET/CT scans of 147 pediatric and adolescent HL patients were interpreted according to the International Harmonization Project Criteria (IHPC) and Deauville Criteria (DC). Two thresholds of positivity were used for the DC: DC-3, scores of 3–5; and DC-4, scores of 4–5. Diagnostic performance of interim and post-treatment PET in outcome prediction was evaluated. Progression-free survival (PFS) was analyzed by the Kaplan-Meier method and Cox proportional hazards model. Results. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of interim FDG-PET/CT were 82%, 33%, 15%, 93%, and 39%, respectively, for IHPC, 82%, 51%, 19%, 95%, and 55%, respectively, for DC-3, and 27%, 78%, 15%, 88%, and 72%, respectively, for DC-4. The corresponding values for post-treatment PET/CT were 73%, 74%, 23%, 96%, and 74% for IHPC, 67%, 80%, 27%, 96%, and 79% for DC-3, and 47%, 90%, 33%, 94%, and 86% for DC-4. PFS significantly differed between patients with positive and negative post-treatment PET/CT according to IHPC, DC-3, and DC-4 (P < 0.01 for all), but only DC-4 was an independent prognostic factor for PFS (hazard ratio: 7.82). Conclusion. Compared to interim PET/CT, post-treatment PET/CT better predicted the outcomes of pediatric and adolescent HL. DC-4 had superior diagnostic performance over IHPC and DC-3.