Prediction of outcome in pediatric Hodgkin lymphoma based on interpretation of ¹⁸FDG-PET/CT according to ΔSUV_max, Deauville 5-point scale and IHP criteria

Objective: Minimizing side effects by using response-adopted therapy strategies plays an important role in the management of pediatric Hodgkin lymphoma (HL); however, the criteria for the definition of adequate or inadequate response are controversial. The aim of this study is to compare different methods of interpretation of ¹⁸F-FDG-PET/CT (PET) in the prediction of disease outcome in order to determine the optimum method in this regard.

Methods: Baseline, interim and post-treatment PET scans of 72 children were interpreted according to revised International Harmonization Project criteria (IHP) and Deauville criteria. Cut-off values for changes in interim and post-treatment FDG uptake (ΔSUV_max) in the prediction of progression-free survival (PFS) were measured using ROC analysis. Quantitative and visual data were compared with each other in the prediction of PFS.

Results: Mean interim and post-treatment ΔSUV_max of the primary lesions were 77.4 ± 19.5 and 68.8 ± 30.4% and respective cut-off values were 82 and 73%. However, only post-treatment ΔSUV_max yielded statistically significant results in the prediction of 3-year PFS (p = 0.043). Interim ΔSUV_max was further analyzed according to the values reported in the literature (66 and 77%) yet statistically significant results were not reached (p = 0.604 and 0.431). For interim evaluation, IHP criteria was correlated to Deauville criteria (p = 0.002 and p = 0.001) and ΔSUV_max (p = 0.03), whereas for post-treatment evaluation, significant correlation with ΔSUV_max (p = 0.04) but marginally significant (p = 0.055 and p = 0.058) correlation with Deauville criteria were achieved. Overall, 1, 3 and 5-year PFS were 95.7 ± 0.2, 89.6 ± 0.4 and 80.8 ± 0.7%, respectively. All methods demonstrated comparable performance in the prediction of 3-year PFS; however, interim PET using Deauville criteria and post-treatment PET using IHP criteria were statistically significant. All methods demonstrated high negative-predictive value but substantially low positive-predictive value.

Conclusions: Deauville criteria are superior to other methods in the prediction of pediatric HL outcome using interim PET data. On the other hand, quantitative evaluation and visual evaluation by IHP can be used reliably at the end of the treatment. In this regard, we report the optimal cut-off value of SUV_max reduction as 73%.