A non-smooth tumor margin on preoperative imaging predicts microvascular invasion of hepatocellular carcinoma

Microvascular invasion (mVI) is known to be a risk factor of hepatocellular carcinoma (HCC) recurrence. Several factors such as the tumor grade, tumor size, tumor margin status on imaging studies, fluorine-18 fluorodeoxyglucose-positron emission tomography (F-18-FDG-PET) results, and tumor markers have been proposed to predict mVI of HCC. However, the values of these factors have not yet been validated. Among the patients evaluated using enhanced CT/MRI, F-18-FDG-PET, and tumor markers prior to hepatectomy from 2007 to 2012, 79 HCC patients without apparent macrovascular invasion in preoperative imaging were enrolled in this study. The image tumor margin status (smooth/non-smooth), F-18-FDG-PET, and tumor markers, which were previously described as predictors for mVI, were evaluated. Fifteen patients had mVI (mVI+ group) and 64 patients had no evidence of mVI (mVI- group) on pathological examinations. A univariate analysis showed that the mVI+ group had a higher SUV and TNR (5.2 vs 3.8, p = 0.02 and 1.8 vs 1.3, p = 0.02, respectively) and a higher portion of non-smooth tumor margin (87 vs 27 %, p = 0.0001). There was no significant difference in the tumor markers. A multivariate analysis showed that non-smooth tumor margin alone could independently predict mVI (odds ratio 18.3, 95 % CI 3.27-102.6, p = 0.0009). A non-smooth tumor margin on preoperative imaging predicts microvascular invasion of HCC.