Role of(18)F-Fluorodeoxyglucose positron Emission Tomography in detecting Extrahepatic Metastasisin pretreatment staging of hin pretreatment staging of hepatocellular carcinoma

Abstract

OBJECTIVES: 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) is useful for differentiating benign from malignant lesions, evaluating tumor stage, monitoring the response to therapy and detecting tumor recurrence in a variety of malignancies. Nevertheless, its use in patients with hepatocellular carcinoma (HCC) is still uncertain. We evaluated whether FDG-PET has a role in detecting extrahepatic metastasis in pretreatment tumor staging of HCC and the characteristics of patients with extrahepatic metastasis that benefit from FDG-PET. METHODS: Eighty-seven patients with HCC underwent computed tomography (CT) or magnetic resonance imaging (MRI) of the abdomen and chest X-ray to evaluate pretreatment tumor staging. FDG-PET was then performed to detect extrahepatic metastasis. The power of FDG-PET to detect extrahepatic metastasis was compared with that of conventional images. In addition, we evaluated whether the detection of extrahepatic metastasis using FDG-PET changed the TNM stage. Moreover, we investigated the clinical and tumor characteristics of patients with extrahepatic HCC metastasis. RESULTS: Extrahepatic metastases were identified in 24 of 87 patients. The location and frequency of metastases were lung 12, lymph nodes 19 and bone 11. All of the extrahepatic metastases were detected by FDG-PET. In addition, FDG-PET identified 4 lymph node metastases and 6 bone metastases that were not found using conventional methods. The initial TNM stage based on the conventional staging workup was changed in 4 cases after FDG-PET. Extrahepatic metastasis was significantly more frequent in patients with intrahepatic tumor >5 cm in size (p = 0.045). CONCLUSIONS: FDG-PET is a useful imaging modality for identifying extrahepatic metastases which may lead to accurate staging and proper management of patients with possible extrahepatic metastases.