18 F-FDG PET/CT predicts survival after 90 Y transarterial radioembolization in unresectable hepatocellular carcinoma.

Purpose: To compare the value of pretreatment functional and morphological imaging parameters for predicting survival in patients undergoing transarterial radioembolization using yttrium-90 ( ⁹⁰ Y-TARE) for unresectable hepatocellular carcinoma (uHCC).
Methods: We analysed data from 48 patients in our prospective database undergoing ⁹⁰ Y-TARE treatment for uHCC (31 resin, 17 glass). All patients underwent ¹⁸ F-FDG PET/CT and morphological imaging (CT and MRI scans) as part of a pretherapeutic work-up. Patients did not receive any treatment between these imaging procedures and ⁹⁰ Y-TARE. Kaplan-Meier estimates of progression-free survival (PFS) and overall survival (OS) were used to assess the prognostic value of ¹⁸ F-FDG PET/CT metabolic parameters, including SUV _max , tumour-to-liver (T/L) uptake ratio and SUV _mean of healthy liver, and morphological data, including number and size of lesions, portal-venous infiltration (PVI). Relevant prognostic factors for HCC including Child-Pugh class, Barcelona Clinic Liver Cancer (BCLC) stage, tumour size, PVI and serum AFP level were compared with metabolic parameters in univariate and multivariate analyses.
Results: The median follow-up in living patients was 16.2 months (range 11.4-50.1 months). Relapse occurred in 34 patients (70.8%) at a median of 7.4 months (range 1.4-27.9 months) after ⁹⁰ Y-TARE, and relapse occurred in 24 of 34 patients (70.8%) who died from their disease at a median of 8.1 months (range 2.2-35.2 months). Significant prognostic markers for PFS were the mean and median lesion SUV _max (both P = 0.01; median PFS 10.2 vs. 7.4 months), and significant prognostic markers for OS were the first quarter (Q1) cut-off values for lesion SUV _max and T/L uptake ratio (both P = 0.02; median OS 30.9 vs. 9 months). The multivariate analysis confirmed that lesion SUV _max and T/L uptake ratio were independent negative predictors of PFS (hazard ratio, HR, 2.7, 95% CI 1.2-6.1, P = 0.02, for mean SUV _max ; HR 2.6, 95% CI 1.1-5.9, P = 0.02, for median SUV _max :) and OS (HR 3.2, 95% CI 1-10.9, P = 0.04 for Q1 SUV _max ; HR 3.7, 95% CI 1.1-12.2, P = 0.03, for Q1 T/L uptake ratio), respectively, when testing with either the BCLC staging system or serum AFP level.
Conclusion: Lesion SUV _max and T/L uptake ratio as assessed by ¹⁸ F-FDG PET/CT, but not morphological imaging, were predictive markers of survival in patients undergoing ⁹⁰ Y-TARE for uHCC.