Healthy Organs Uptake on Baseline 18F-FDG PET/CT as an Alternative to Total Metabolic Tumor Volume to Predict Event-Free Survival in Classical Hodgkin's Lymphoma

Abstract

PurposeHealthy organs uptake, including cerebellar and liver SUVs have been reported to be inversely correlated to total metabolic tumor volume (TMTV), a controversial predictor of event-free survival (EFS) in classical Hodgkin's Lymphoma (cHL). The objective of this study was to estimate TMTV by using healthy organs SUV measurements and assess the performance of this new index (UF, Uptake Formula) to predict EFS in cHL.MethodsPatients with cHL were retrospectively included. SUV values and TMTV derived from baseline 18F-FDG PET/CT were harmonized using ComBat algorithm across PET/CT systems. UF was estimated using ANOVA analysis. Optimal thresholds of TMTV and UF were calculated and tested using Cox models.Results163 patients were included. Optimal UF model of TMTV included age, lymphoma maximum SUVmax, hepatic SUVmean and cerebellar SUVmax (R2 14.0% - p < 0.001). UF > 236.8 was a significant predictor of EFS (HR: 2.458 [1.201–5.030], p = 0.01) and was not significantly different from TMTV > 271.0 (HR: 2.761 [1.183–5.140], p = 0.001). UF > 236.8 remained significant in a bivariate model including IPS score (p = 0.02) and determined two populations with different EFS (63.7 vs. 84.9%, p = 0.01).ConclusionThe Uptake Formula, a new index including healthy organ SUV values, shows similar performance to TMTV in predicting EFS in Hodgkin's Lymphoma. Validation cohorts will be needed to confirm this new prognostic parameter.

Prognostic Value of Baseline Tumor Burden and Tumor Dissemination Extracted From 18F-FDG PET/CT in a Cohort of Adult Patients With Early or Advanced Hodgkin Lymphoma

“…24 Regarding TMTV, this PET feature was confirmed in our study as prognostic factor for PFS in the univariate analysis, which is consistent with almost all studies assessing baseline TMTV as risk factor in HL, [10][11][12][14][15][16][17][18] especially the recent studies including patients treated with escalated BEACOPP. 13,19,20 The presence of a bulky tumor was not a predictor of a poor outcome in our study, confirming that quantifying the volume rather than the single largest diameter of the mass gives a more relevant prognosis information. However, the cutoff value of TMTV parameter discriminating high-and low-risk groups in our study differs from that described in the 3 other studies, including also early and advanced HL patients (107 cm 3 vs 33 cm 310 vs 225 cm 316 vs 271 cm 3 ).…”

“…However, the cutoff value of TMTV parameter discriminating high-and low-risk groups in our study differs from that described in the 3 other studies, including also early and advanced HL patients (107 cm 3 vs 33 cm 310 vs 225 cm 316 vs 271 cm 3 ). 19 However, we applied the same segmentation method (tumor delineation threshold set at 41% of the SUV max ) and the same feature dichotomization method (based on ROC curve) as performed in the other studies. The few observed events and the small size of the study population reported in the different studies might be the explanation to this discordancy.…”

“…PET/CT images were analyzed, and quantitative parameters were extracted by a nuclear medicine physician using Syngo.via software (Siemens Healthineers). Metabolic tumor volumes (MTVs) were defined using 41% SUV max threshold in accordance with the recommendations of the European Association of Nuclear Medicine 26 and with most of the studies that assessed TMTV in HL 10,11,13–19 . TMTV was defined as the sum of every individual lesion metabolic volume.…”

“…Metabolic tumor volumes (MTVs) were defined using 41% SUV max threshold in accordance with the recommendations of the European Association of Nuclear Medicine 26 and with most of the studies that assessed TMTV in HL. 10,11,[13][14][15][16][17][18][19] TMTV was defined as the sum of every individual lesion metabolic volume. The TLG was calculated as the sum of the product of MTV of each lesion and its SUV mean .…”

“…[10][11][12][14][15][16][17][18] However, since the introduction of escalated BEACOPP for patients with advanced HL, the role of TMTV is debated. Three studies showed that TMTVs have a significant impact in predicting PFS, 10,11,13,19,20 but 1 publication reported no association between TMTVand PFS. 21 Regarding TLG, only 1 study assessed this feature as prognostic factor for HL patients treated with escalated BEACOPP and showed a significant association of TLG with PFS.…”