Imaging of primary liver tumors with positron-emission tomography.

INTRODUCTION: The use of positron-emission tomography (PET) with fluorodeoxyglucose (FDG), 11C-acetate and radio-labelled choline such as 11C-choline or 18F-fluorocholine in the diagnosis of hepatocellular carcinoma (HCC), for risk stratification or therapy monitoring has emerged. This review aims to summarize the published results dealing with this issue.

EVIDENCE ACQUISITION: PubMed database was searched until February 2017. Sensitivities, specificities, progression-free survival (PFS), survival and hazard ratios (HR) are reported.

EVIDENCE SYNTHESIS: Seventy-one studies were included. Most studies are dealing with the diagnostic value of FDG PET (N.=21), 11C-acetate PET (N.=11), and choline PET (N.=8). The results indicate a homogenously higher sensitivity for 11C-acetate and choline PET as compared to FDG PET in the diagnosis of primary or recurrent HCC. This is particularly true for well differentiated HCC, which tend to have higher uptake of 11C-acetate and radio-labelled choline. Contrary, poorly differentiated HCC are more often FDG-positive than well differentiated HCC. Sixteen studies are evaluating the prognostic value of FDG PET for surgery or liver transplantation. The studies found a significant worse prognosis in terms of time to recurrence, PFS, and survival in FDG-positive HCC as compared to FDG-negative ones. Sixteen studies are reporting about the prognostic value of FDG PET and one about 18F-fluoroethylcholine PET for palliative treatment. Most of these studies indicate a significant shorter PFS and survival in FDG-positive HCC for various treatments.

CONCLUSIONS: Whereas FDG PET has only a limited role in the diagnosis of HCC, it provides valuable prognostic information for liver surgery, transplantation and palliative treatment. 11C-acetate and choline PET have a higher sensitivity in the diagnosis of HCC.