The difference of clinicopathologic factors between FDG-avid and non-FDG-avid hepatocellular carcinoma without extrahepatic metastasis

Objectives Lots of hepatocellular carcinomas (HCC) were demonstrated as non-FDG-avid tumors regardless of the tumor size in FDG PET/CT. The aim of this study is to know the difference in clinicopathologic factors between FDG-avid and non-avid HCC.

Methods Fifty-six patients (M: F = 44: 12, 63.4 ± 8.9 years old) with nodular HCC and without extrahepatic metastasis who underwent pretreatment FDG PET/CT were enrolled. The patients were classified into two groups, FDG-avid and non-avid groups, according to FDG-avidity by visual assessment. Then the difference in imaging, clinical and pathologic factors between two groups was evaluated.

Results In FDG PET/CT, among 56 patients, HCC was detected in 39 patients (69.6%, FDG-avid group) and was not detected in 17 patients (30.4%, non-FDG-avid group). The mean size of the tumor was 6.5 ± 3.8 cm in FDG-avid group and 3.9 ± 2.7 cm in non-FDG-avid group, respectively. The mean SUVmax was 6.5 ± 3.7 (median: 5.1, range: 2.5 - 19.8) in FDG-avid group. Among the analyzed factors including sex, age, tumor size, cause of cirrhosis, AFP, PIVKA, differentiation, Child-Pugh class, death from HCC, recurrence, portal vein thrombus, tumor number, modality of treatment, SUVmax and tumor-to-background ratio, there was significant difference in tumor size (p < 0.01), cause of cirrhosis (alcohol vs virus, p = 0.04), portal vein thrombus (p = 0.04) and death from HCC (p = 0.03) in univariate analysis. Among them, tumor size (p = 0.02) and cause of cirrhosis (alcohol: virus = 7: 10 in non-FDG-avid group vs 5: 34 in FDG-avid group, p = 0.03) were significant different in multivariate analysis.

Conclusions There are significant differences in tumor size, presence of PV thrombus, death from HCC and cause of cirrhosis in univariate analysis, and tumor size and cause of cirrhosis in multivariate analysis. The etiology of liver cirrhosis could be considered as one of factors influence FDG uptake in HCC. Further studies are required in regard to the relationship between FDG-avidity and cause of cirrhosis.