Introduction: Numerous clinical and FDG-PET/CT-associated models were proposed to predict treatment failure in Hodgkin's lymphoma (HL). Baseline quantitative FDG-PET metrics are emerging biomarkers showing promising prognostic value. We retrospectively analysed the impact of tumour bulk and dissemination as measured by assessing Metabolic Tumor Volume (MTV) and D max - the distance between the furthest lesions identified by FDG-PET/CT - on the probability of progression in HL patients in clinical stages II to IV.
Methods: Baseline FDG-PET/CT data of 117 patients with newly diagnosed HL from the PLRG-11 study was analysed and MTV was assessed by manual segmentation with the volume of interest (VOI) threshold of 41%SUVmax and Dmax was calculated by measuring the diameter between centroids of VOIs with SUVmax above SUVmax of the liver located furthest apart. The Median follow-up was months. The distance was measured in 3-dimensional space using Euclidean geometry. The cut-off values of MTV and Dmax were calculated with the maximally selected rank statistic method.
Results: MTV cut-off value for progression-free survival (PFS) prediction was 214 ml with PPV 0,516 and NPV of 0.848 and for Dmax was 10 cm with PPV 0.291 and NPV of 1.0. In the cohort of 69 patients with negative interim PET/CT performed post-second cycle of ABVD PFS event was reported in 0% and 17% patients with Dmax below and above 10 cm, respectively and in 6% and 36% of patients with MTV below and above threshold value of 214 ml, respectively.
Conclusion: Bulk and dissemination assessments in baseline PET/CT in Hodgkin lymphoma stage II-IV patients may help identify a population of patients with an especially good prognosis.