Prognostic impact of metabolic tumor volume using the SUV4.0 segmentation threshold in 1,960 lymphoma patients from prospective LYSA trials.

Abstract

This study compared the prognostic value of total metabolic tumor volume (TMTV) in lymphoma measured with the recently proposed SUV4.0 segmentation threshold versus the 41% SUVmax across LYSA trials and its impact on intensity and dissemination PET features. A total of 1960 baseline PET/CT scans of Diffuse Large B cell lymphoma (DLBCL), follicular lymphoma (FL) and Hodgkin lymphoma (HL) patients were collected. After a semi-automatic preselection of region of interest, two different segmentation threshold were applied: 41% SUVmax (TMTV_41%) and SUV > 4.0 (TMTV_4.0). The correlation between TMTV_4.0 and TMTV_41% was ρ = 0.90 for DLBCL, ρ = 0.65 for FL and ρ = 0.60 for HL. For SUVmax, SUVpeak, Dmax and Dbulk features, a strong correlation was observed with ρ > 0.95 whatever the lymphoma subtypes. The predictability of TMTV was high and comparable for the two methods with superimposable confidence intervals for the three subtypes. At the 90th percentile TMTV value, the predicted 7-year PFS was 51.13% with TMTV_4.0 vs. 49.7% with TMTV_41% for DLBCL patients, 45.5% vs. 39.8% for FL patients, and 82.6% vs. 80.5% for HL patients. A minority of patients showed a predicted PFS deviation > 10% between the two methods: 2.33% in DLBCL, 6.51% in FL and 1% in HL. TMTV measured with the SUV4.0 threshold provides a comparable PFS prediction than the 41%SUVmax method supporting its routine adoption particularly in the diffuse large B cell lymphoma subtype.