18F-Fluorodeoxyglucose PET/CT predicts tumour progression after transarterial chemoembolization in hepatocellular carcinoma

Purpose F-18-FDG PET monitoring of FDG uptake may be a useful tool for assessment of the biological behaviour of hepatocellular carcinoma (HCC). We evaluated the correlation between FDG uptake on F-18-FDG PET and clinical characteristics and prognosis. Methods In total, 58 HCC patients undergoing F-18-FDG PET before transarterial chemoembolization (TACE) between May 2007 and May 2010 at Seoul St. Mary's Hospital were evaluated retrospectively. The predictive value of the ratio of maximal tumour standardized uptake value (SUV) to mean liver SUV (TSUVmax/LSUVmean) was tested. Primary endpoints were the clinical characteristics and treatment response according to TSUVmax/LSUVmean. The secondary endpoint was time to progression (TTP). Results A high SUV ratio (cutoff value 1.70) correlated significantly with tumour size (>= 5 cm) and serum AFP level (>= 400 ng/mL). Objective response rates were significantly different between those with a ratio above (15.7 %) and those with a ratio below (66.6 %) the cutoff value (P=0.023). Patients in the low SUV ratio group had a median TTP of 16.8 months compared with 8.1 months in the high SUVratio group (P=0.011). Overall survival in the high SUV ratio group was worse than in the low SUV ratio group (median 56.5 vs. 23.3 months), although the difference was not statistically significant in a multivariate analysis. Conclusion Tumour metabolic activity (TSUVmax/LSUVmean), assessed by PET/CT, is an independent predictor of response to TACE in patients with intermediate-stage HCC. TSUVmax/LSUVmean can be used to predict tumour progression. Thus, F-18-FDG PET can provide valuable information for prediction of prognosis and aid in decisions regarding treatment strategy.