Value of 18F-FDG PET/CT in detecting viable tumour and predicting prognosis of hepatocellular carcinoma after TACE

Abstract

To evaluate the efficacy of combined PET/CT in the detection of viable tumour in patients with hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE). The correlation between 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) uptake during PET and prognosis was evaluated. Seventy-three patients with 91 HCCs who had undergone TACE with lipiodol before (18)F-FDG PET/CT were retrospectively reviewed. The pattern of lipiodol deposition in the tumour was divided into three groups: grade I, lipiodol remaining in ≥60% of the tumour; grade II, 20-60%; and grade III, ≤20%. The performance of (18)F-FDG PET/CT in evaluating the viability of HCC was assessed and compared with that of contrast-enhanced CT (CECT). The predictive value of maximal tumoural standardized uptake value (SUV) to mean liver SUV (TSUVmax/LSUVmean) ratio was tested. Comparing the receiver-operating characteristic area, (18)F-FDG-PET/CT was found to be superior to CECT for the detection of viable tumour in patients with HCC after TACE (p=0.04). A high SUV ratio (TSUVmax/LSUVmean ≥1.65) correlated significantly with tumour size (p=0.0096), the grade of lipiodol deposition (p=0.0387) and serum α-foetoprotein (AFP) level (p=0.0142), but did not correlate with pathological grade (p=0.2626). The overall survival rate was significantly higher in the low SUV ratio (TSUVmax/LSUVmean<1.65) group (p=0.024). (18)F-FDG-PET/CT is efficient in assessing the viability of HCC after TACE and is superior to CECT in grades I and II, and similar in grade III. It provides valuable information for prediction of prognosis and may aid decisions regarding treatment strategy.