High values of baseline volumetric PET biomarkers in classical Hodgkin's lymphoma as predictors of unfavourable prognosis

Abstract

Purpose: To analyse the prognostic value of the initial volumetric PET biomarkers – the total metabolic tumor volume (MTV) and the total lesion glycolysis (TLG) – in classic Hodgkin's lymphoma (cHL) and determine their optimal threshold values for prognosis.Material and methods. This retrospective study included 62 cHL patients with different stages who underwent staging with 18F-FGD PET/CT. The follow-up period was from 6 to 61 months after the baseline PET/CT, 41 patients remained in remission, 10 patients had refractory course, 11 relapsed. The examinations were processed with automatic (multi-foci segmentation – MFS) method to obtain MTV and TLG using two fixed absolute thresholds (SUVmax ≥ 2.5 and SUVmax ≥ 4.0) and one relative threshold (41% of SUVmax).Results. In subgroups with disease remission (n = 41) and refractory course or relapse (n = 21), statistically significant differences between MTV and TLG with the two thresholds were found – SUVmax ≥ 2.5 and 41% of SUVmax (p < 0.05). When using threshold of SUVmax ≥ 4.0 statistically differences between the mean of MTV and TLG were no detected.Univariate analysis revealed correlation between progression-free survival and volumetric PET biomarkers (MTV and TLG) with three thresholds (SUVmax ≥ 2.5, SUVmax ≥ 4.0, and 41% of SUVmax).Conclusion. In cHL high values of initial volumetric PET biomarkers – MTV and TLG – calculated with three thresholds (SUVmax ≥ 2.5, SUVmax ≥ 4.0, and 41% of SUVmax) are associated with unfavourable prognosis – a high probability of refractory disease course or relapse.The optimal prognostic thresholds values of MTV and TLG in the analysed group were determined respectively: SUVmax ≥ 2.5 – 204 cm3 and 961, at 41% of SUVmax – 105 cm3 and 620.