Role of ¹⁸F-Fluorodeoxyglucose Positron Emission Tomography in Detecting Extrahepatic Metastasis in 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.

18F-FDG PET CT as a prognostic factor in hepatocellular carcinoma

“…Increased TSUVmax/MSUVmean ratio also correlated well with higher stages of disease in both the TNM and BCLC staging systems. These findings are compatible with other studies using tumor SUV or the tumor to non-tumor SUV ratio as parameters to predict the tumor characteristics (24,34,35).…”

Asian Pacific Association for the Study of the Liver consensus recommendations on hepatocellular carcinoma

“…The role of positron emission tomography (PET) in the diagnostic and staging evaluation of HCC still remains uncertain. Several studies have suggested a role for [ 18 F]fluorodeoxyglucose (FDG)-PET scanning for the detection of primary HCCs, tumor staging, assessing response to therapy, and for predicting prognosis [231][232][233]. HCCs accumulate FDG to varying degrees (only 55-65% of tumors give a positive result by PET scanning), limiting the sensitivity of PET for primary tumors [234,235].…”

“…HCCs accumulate FDG to varying degrees (only 55-65% of tumors give a positive result by PET scanning), limiting the sensitivity of PET for primary tumors [234,235]. However, FDG-PET seems to be a useful imaging modality for identifying extrahepatic metastases, although sensitivity is limited for lesions 1 cm or smaller [231,236]. …”

FDG positron emission tomography/computed tomography findings for the prediction of early recurrence of hepatocellular carcinoma after surgical resection

“…The ability of PET to detect HCC in the liver was found to be less effective than that of contrast enhanced CT (14). On the other hand, yoon et al (15) and Sugiyama et al (16) reported that PET is useful for the screening of extrahepatic metastasis from HCC. Recently, the usefulness of FDG-PET for predicting HCC recurrence following liver transplantation was proposed (17,18).…”

“…Full body scanning with PET/CT is useful for the screening of extrahepatic metastasis and staging in patients with large HCC (15). An FDG-PET/CT examination is non-invasive and useful for predicting the malignant pathological potential of HCC before resection without the need for a biopsy.…”