FDG PET/CT as a prognostic test after 90Y radioembolization in patients with metastatic hepatic disease.

The purpose of this study was to determine FDG PET/CT utility in predicting patient outcome undergoing Y-90 RE for metastatic liver tumors. Thirty-one patients with metastatic tumors to the liver underwent Y-90 RE between March 15, 2007, and May 5, 2011, at our institution. FDG PET/CT imaging was performed on each patient within 3 months before and after undergoing Y-90 RE. Pretreatment and posttreatment FDG PET/CT were evaluated for SUV, number of liver lesions, and presence of disease outside the liver. The Kaplan-Meier method and Cox proportional hazard modeling was used to evaluate if SUV was a predictor of overall survival. Of the 31 patients, 12 were alive at the end of the study; median survival was 9 months (95% confidence interval, 7-18 months). The 24-month survival rate was 0.28 (95% confidence interval, 0.12-0.48). Kaplan-Meier analysis of preprocedure FDG PET/CT imaging showed no difference in rates of survival by number of lesions observed in the liver (P = 0.114) or presence of disease observed outside the liver (P = 0.719). Cases with new lesions outside the liver after treatment had significantly shorter survival times than cases without new lesions outside the liver (P = 0.002). Cox proportional hazard model showed that SUV levels before and after treatment were not significant predictors of overall survival. The appearance of new lesions outside the liver on FDG PET/CT within 3 months after Y-90 RE was the only statistically significant variable in predicting poor outcome. Absence of new lesions outside the liver on postprocedure FDG PET/CT imaging helps identify patients achieving long-term survival.