Aim of work: Evaluate the prognostic value of baseline and interim volume-based 18 fluorine-labeled fluoro-2-deoxyglucose positron emission tomography (18F-FDG PET) metabolic parameters in paediatric patients diagnosed with bulky and advanced Hodgkin lymphoma (HL), in respect to patients' progression-free survival, and their role in predicting early metabolic therapy response.
Patients and Methods: Aretrospective study of a total of 59 paediatric patients with bulky and advanced stages HL who performed upfront and interim PET/CT scans. PET/CT parameters: maximum standardized uptake value (SUVmax), SUVmean, SUVpeak, metabolic tumour volume (MTV), and total lesion glycolysis (TLG) were extracted. Initial whole-body MTV and TLG were calculated. Early response assessment using Deauville scoring systems was used to evaluate interim 18F-FDG PET/CT scan. Prediction of early therapy response and progression free survival of these parameters were evaluated.
Results: Baseline albumin level predicted therapy response. Initial SUVmax and SUVpeak in bulky disease (P values=0.036 for both) were the only PET parameters that predicted therapy response and Progression-free survival. All the interim parameters with the changes between initial and interim quantitative PET/CT parameters are statistically significant and succeeded to predict 1.5 year- PFS in the advanced group. In the bulky group only the interim TMTV and TLG maintained their statistical significance. Baseline whole body MTV and TLG ROC curves failed to predict therapy response and progression-free survival (PFS) for both groups. Regarding clinical outcome, interim 18F-FDG PET/CT Deauville scoring system was found to be statistically significant(p <0.001).
Conclusion: Interim PET/CT in paediatric Hodgkin lymphoma revealed that Deauville score remains the best indicator for prediction of therapy response. All the interim parameters & the changes between initial and interim quantitative parameters succeeded to predict 1.5 year- PFS in the advanced group. Baseline PET/CT (SUVmax and SUVpeak) is suggested to predict response to therapy in paediatric patients with bulky disease.