Abstract
The Children's Oncology Group AHOD0831 study used a positron emission tomography (PET) response-adapted approach in high-risk Hodgkin lymphoma, whereby slow early responders (SERs) received more intensive therapy than rapid early responders (RERs). We explored if baseline PET-based characteristics would improve risk stratification. Of 166 patients enrolled in the COG AHOD0831 study, 94 (57%) had baseline PET scans evaluable for quantitative analysis. For these patients, total body metabolic tumour volume (MTV), total lesion glycolysis (TLG), maximum standardized uptake value (SUV(max) ) and peak SUV (SUV(peak) ) were obtained. MTV/TLG thresholds were an SUV of 2.5 (MTV(2.5) /TLG(2.5) ) and 40% of the tumour SUV(max) (MTV(40%) /TLG(40%) ). TLG(2.5) was associated with event-free survival (EFS) in the complete cohort (p = 0.04) and in RERs (p = 0.01), but not in SERs (p = 0.8). The Youden index cut-off for TLG(2.5) was 1841. Four-year EFS was 92% for RER/TLG(2.5) up to 1841, 60% for RER/TLG(2.5) greater than 1841, 74% for SER/TLG(2.5) up to 1841 and 79% for SER/TLG(2.5) greater than 1841. Second EFS for RER/TLG(2.5) up to 1841 was 100%. Thus, RERs with a low baseline TLG(2.5) experienced excellent EFS with less intensive therapy, whereas RERs with a high baseline TLG(2.5) experienced poor EFS. These findings suggest that patients with a high upfront tumour burden may benefit from intensified therapy, even if they achieve a RER.