Comparison of 18F-FDG-PET and standard procedures for the pretreatment staging of children and adolescents with Hodgkin's disease

Purpose: The aim of this study was to perform a prospective, blinded comparison of F-18-fluorodeoxyglucose positron emission tomography (FDG-PET) and conventional staging methods (CSMs) for initial staging of children and adolescents with Hodgkin's disease (HD). Methods: Over a period of 4 years, 55 children and adolescents with HD (mean age 15.5 years, range 3.9-18.9 years) were prospectively recruited into the study. They underwent 61 FDG-PET studies using a dedicated whole-body PET scanner as a part of their initial staging work-up. PET findings were correlated with the results of CSMs, including computed tomography (CT), ultrasound, bone scanning and bone marrow examination. Discordant findings were resolved by magnetic resonance imaging or clinical follow-up (range 2-47 months). Results: PET correctly changed the staging in 15% of patients (seven upstagings, two downstagings). Only two out of 61 patients (3%) were not accurately staged by PET; in these children, PET missed small lymphoma nodules detected on lung CT. The sensitivity of PET and CSMs for pretreatment staging was 96.5% and 87.5%, respectively; specificity was 100% and 60%, and accuracy, 96.7% and 85.2%, respectively. Upon combination of FDG-PET and lung CT, the diagnostic accuracy reached 100% in our series. Conclusion: Our study showed that whole-body FDG-PET is an efficient and useful method for the initial staging of children with HD. FDG-PET in combination with lung CT should be recommended as a screening method prior to other conventional imaging modalities to plan a rational staging protocol. Large multicentre prospective studies are necessary to verify this conclusion.