Multimetabolic 18F-Fluorodeoxyglucose (FDG) and 18F-Fluorocholine (FCH) Positron Emission Tomography (PET) as an Early Predictive Factor of Overall Survival in Patients With Advanced Hepatocellular Carcinoma Treated With Sorafenib

Hepatocellular carcinoma (HCC) is the third cause of death by cancer. For patients with inoperable advanced HCC, systematic therapy with Sorafenib, a multikinase inhibitor that has both antiangiogenic and antiproliferative effect, is the only therapeutic with proven survival benefits. However, the efficacy of Sorafenib remains inconstant with a media overall survival of 10,7 months and a disease control rate only 35 to 43%; moreover, the overall incidence of treatment-related adverse event is 80%. Thus, it appears essential to find an early and accurate way to determine which patients are best responding to therapy in order to avoid the toxicity and cost of ineffective therapy. Positron Emission Tomography (PET) with 18F-Fluorodeoxyglucose (FDG) has shown limited performance in the setting of HCC because of lack of sensitivity, in particular for well-differentiated tumours. However FDG uptake is related to proliferation rate and is an efficient marker survival following liver transplantation and selective internal radiation therapy. Moreover, the addition of a dynamic first-pass acquisition to the standard static scan provides better characterization of the tumour by adding information on tumour perfusion. FCH which reflects lipids metabolism and specifically choline kinase activity, has shown promising results for detection of HCC when compared with FDG alone. Moreover, choline activity is related to a kinase pathway in mammalian cells, which is specifically inhibited by Sorafenib. However FCH uptake remains inconstant in HCC, and is related to tumour differentiation, by opposition to FDG. Therefore, several studies have suggested that combined evaluation of tumour glucose and lipid metabolism could play a complementary role for the evaluation of HCC in the setting of detection, staging and to predict recurrence following surgical resection. Thus, the investigator hypothesize that the combination of FDG and FCH may be the most accurate imaging evaluation of HCC.