Positioning of 18F-fluorodeoxyglucose-positron emission tomography imaging in the management algorithm of hepatocellular carcinoma.

Background And Aim: (18) F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) may detect primary lesions (PLs) and extrahepatic metastases (EHMs) only in advanced hepatocellular carcinoma (HCC) patients. We investigated the requirement of PET and the optimal timing of PET scanning for accurate staging and treatment planning.

Methods: We conducted a retrospective investigation of 64 HCC patients who underwent PET (median age, 74 years; male/female, 41/23; etiology, 46 hepatitis C virus/4 hepatitis B virus/4 alcoholic/10 others). To determine the best timing for PET examinations, we analyzed PET result-based recommended treatment changes and characteristics of patients with FDG-avid PLs or EHMs.

Results: FDG-avid PLs were detected by PET in 22 patients (34%): 18 with hypervascular PL, 11 with serum α-fetoprotein levels ≥ 200 ng/mL, and 11 beyond Milan criteria. EHMs were detected in 21 patients (33%: lymph nodes, 8; lung, 5; abdominal wall, 4; bone, 3; other organs, 4 [including overlapping]). Recommended treatments changed for 16 patients (25%) because of Barcelona Clinic Liver Cancer stage increases based on PET scanning. In multivariate analyses, serum α-fetoprotein levels ≥ 200 ng/mL and beyond Milan criteria were independent factors for FDG-avid PLs and a maximum standardized uptake value (SUVmax) of PLs of ≥ 4.0 was an independent factor for FDG-avid EHMs (P = 0.002, 0.008, and 0.045, respectively).

Conclusions: PET allows detection of HCC spread in patients with elevated serum α-fetoprotein levels or those beyond Milan criteria and detects EHMs in patients with PLs with high SUVmax values. Optimally timed PET scans can complement conventional imaging for accurate staging and treatment strategy determination.