Objectives: The present study was designed to assess the usefulness of positron emission tomography with fluorine-18-fluorodeoxyglucose (FDG-PET) for predicting outcome in patients with hepatocellular carcinoma.
Methods: FDG-PET was performed in 48 patients with hepatocellular carcinoma. For quantitative evaluation, a region of interest (ROI) was placed over the area of maximum activity within the lesion. A background ROI was then placed over the nontumor region of the liver. The average activity within each ROI was subsequently corrected for radioactive decay, and the standardized uptake value (SUV) was calculated by dividing the tissue activity by the injected dose of radioactivity per unit body weight. SUV ratio was expressed as the tumor-to-nontumor ratio of the SUV.
Results: The tumor-volume doubling time, as index of the growth rate of hepatocellular carcinoma, correlated significantly with SUV ratio but did not correlate with SUV. On the basis of the SUV ratio, the patients were divided into two groups of similar size: group A, SUV ratio of < or = 1.5; and group B, SUV ratio > 1.5. The cumulative survival rate was significantly lower in group B than in group A. On the basis of the SUV, the patients were divided into two groups of roughly equal size: group C, < or = SUV 2.6; and group D, > SUV 2.6. The cumulative survival rate was similar in these groups. On regression analysis with the Cox proportional hazards model, the SUV ratio and tumor number were significantly related to survival.
Conclusions: These results suggest that FDG-PET is useful not only for the evaluation of the malignancy of hepatocellular carcinoma but also for the prediction of outcome in patients with hepatocellular carcinoma.