Prognostic Value of FDG Uptake of Portal Vein Tumor Thrombosis in Patients with Locally Advanced Hepatocellular Carcinoma

Purpose This study aimed to evaluate the prognostic value of ¹⁸F-FDG uptake of portal vein tumor thrombosis (PVTT) for predicting progression-free survival (PFS) and overall survival (OS) in patients with locally advanced hepatocellular carcinoma (HCC). Methods The study retrospectively included 166 HCC patients with PVTT and no extrahepatic metastases who underwent staging FDG PET/CT. Tumor-to-liver uptake ratio (TLR) and PVTT-to-liver uptake ratio (PLR) were measured for each patient, and the prognostic values of clinical factors, TLR, and PLR were assessed. Furthermore, patients were classified into 2 subgroups according to TLR, and the prognostic value of PLR was evaluated in each subgroup. Results Median PFS and OS were 6.2 and 10.1 months, respectively. On multivariate analysis, tumor size (P = 0.006) and PLR (P = 0.03) were independent prognostic factors for PFS, whereas Child-Pugh class (P = 0.02) and PLR (P = 0.02) were independent prognostic factors for OS. Tumor-to-liver uptake ratio was a significant prognostic factor for PFS and OS on univariate analysis but failed to show significance on multivariate analysis. In both patient subgroups with low and high TLR, PLR remained a significant prognostic factor for predicting OS (P = 0.04 for all). Conclusions FDG uptake of PVTT, but not FDG uptake of HCC, is an independent prognostic factor for PFS and OS in HCC patients with PVTT and no extrahepatic metastasis. Given the prognostic significance, it is strongly encouraged to use FDG uptake of PVTT in further risk stratification for HCC patients with PVTT.