Prognostic value of baseline metabolic tumor volume in early stage Hodgkin's lymphoma in the standard arm of H10 trial

We tested baseline PET/CT as a measure of total tumor burden in order to better identify high risk patients in early-stage Hodgkin's lymphoma (HL). Stage I-II HL patients enrolled in the standard arm (combined modality treatment) of the H10 trial (NCT00433433) with available baseline PET and interim PET (iPET2) after two cycles of doxorubicine, bleomycin, vinblastine, dacarbazine were included. Total metabolic tumor volume (TMTV) was measured on baseline PET. IPET2 findings were reported negative (DS1-3) or positive (DS4-5) with the Deauville scale. The prognostic value of TMTV was evaluated and compared to baseline characteristics, staging classifications and iPET2. A total of 258 patients were eligible, 101 favorable and 157 unfavorable. The median follow-up was 55 months, with 27 PFS and 12 OS events. TMTV was prognosticator of PFS (p<0.0001) and OS (p=0.0001) with an 86% and 84% specificity respectively. The 5y-PFS and OS were 71% and 83% in the high TMTV (>147cm3) group (n=46) vs. 92% and 98% in the low TMTV group (≤147cm3). In multivariable analysis including iPET2, TMTV was the only baseline prognosticator compared to the current staging systems proposed by EORTC/GELA, GHSG, or NCCN groups. TMTV and iPET2 were independently prognostic and combined identified four risk groups: low (TMTV≤147+DS1-3; 5y-PFS 95%), low-intermediate (TMTV>147+DS1-3; 5y-PFS 81.6%), high-intermediate (TMTV≤147+DS4-5; 5y-PFS 50%) and high (TMTV>147+DS4-5; 5y-PFS 25%). TMTV improves baseline risk stratification of early stage HL patients compared to current staging systems and the predictive value of early PET response as well.