¹⁸F-FDG PET/CT But Not Morphological Parameters Predict Survival after Yttrium-90 Transarterial Radioembolization in Unresectable Hepatocellular Carcinoma: an updated analysis.

Objectives: To investigate the role of pre-therapeutic anatomic versus functional imaging in predicting survival in patients undergoing transarterial radioembolization using Yttrium-90 (⁹⁰Y-TARE) for unresectable HCC (uHCC).

Methods: We analyzed data of 55 patients of our prospective database (48 men; median age, 68.1; range, 24 - 87 years) undergoing ⁹⁰Y-TARE treatment for uHCC (37 resin, 18 glass). All patients underwent ¹⁸F-FDG PET/CT and CT and/or MRI scans as part of a pre-therapeutic work-up. Patients did not receive any treatment between these imaging procedures and ⁹⁰Y-TARE. Prognostic value of ¹⁸F-FDG PET/CT metabolic parameters (SUV_max, tumor-to-liver [T/L] uptake ratio, SUV_mean of healthy liver) and anatomic MRI or CT data (number and size of lesions, portal-venous infiltration [PVI]) was assessed by Kaplan-Meier estimates of progression-free survival (PFS) and overall survival (OS) and compared using the log-rank test. Furthermore the influence of relevant prognostic factors for HCC including Child-Pugh class, Barcelona Clinic Liver Cancer (BCLC) staging system, tumor size, PVI and serum AFP level compared to imaging on PFS and OS parameters was analyzed using COX multivariate analysis.

Results: Median follow-up in living patients was 17.5 months (mo) (range, 1-50.1 mo). Relapse occurred in 39 patients (71%) at a median of 7.4 mo (range, 1.4-27.9 mo) after ⁹⁰Y-TARE. Fourty patients (73%) died from their disease at a median of 7.7 mo (range, 2.2-35.2 mo) and relapse occurred in 28 (70%) of them. The prognostic markers were: i) the mean SUV_max lesion with a median PFS of 10.2 mo (95% CI 6.6-13.8 mo) in patients with a cutoff value < 7.7 g/mL vs. 7.4 mo (95% CI 3-11.7 mo) in patients with a mean SUV_max lesion cutoff 蠅 7.7 g/mL (p=0.01) and ii) the T/L ratio with a median OS of 30.9 mo (95% CI 11.2-50.9 mo) in patients with a 1^st quarter (Q1) cutoff value < 2.0 vs. 8.9 mo (95% CI 7.4-10.4) in patients with a Q1 cutoff value 蠅 2 (p=0.02). In multivariable analysis, only the cutoff value of the mean SUV_max lesion and the Q1 T/L ratio were significant independent predictors of PFS (p=0.01) and OS (p=0.04) respectively when testing with either Child-Pugh class, the BCLC staging system and the serum AFP level.

Conclusion: SUV_max lesion and T/L uptake ratio as assessed by ¹⁸F-FDG PET/CT, but not anatomic imaging were predictive markers of survival in patients undergoing ⁹⁰Y-TARE for uHCC. Research Support: none