Baseline metabolic tumour burden improves risk stratification in Hodgkin lymphoma: A Children's Oncology Group study

Abstract

SummaryThe 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 (SUVmax) and peak SUV (SUVpeak) were obtained. MTV/TLG thresholds were an SUV of 2.5 (MTV2.5/TLG2.5) and 40% of the tumour SUVmax (MTV40%/TLG40%). TLG2.5 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 TLG2.5 was 1841. Four‐year EFS was 92% for RER/TLG2.5 up to 1841, 60% for RER/TLG2.5 greater than 1841, 74% for SER/TLG2.5 up to 1841 and 79% for SER/TLG2.5 greater than 1841. Second EFS for RER/TLG2.5 up to 1841 was 100%. Thus, RERs with a low baseline TLG2.5 experienced excellent EFS with less intensive therapy, whereas RERs with a high baseline TLG2.5 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.