Microvascular invasion in patients with hepatocellular carcinoma and its predictable clinicopathological factors.

Macroscopic vascular invasion is known to be a poor prognostic factor in hepatocellular carcinoma (HCC). The aim of this study was to determine the outcomes and predictive factors after hepatic resection for HCC with microvascular invasion (MVI). One hundred ten patients who underwent curative resection for HCC without macroscopic vascular invasion were included in this retrospective study. The risk factors of these patients for recurrence-free and disease-specific survival were investigated, and the clinicopathological factors predicting the presence of MVI were also determined. Of the 110 resected specimens, 49 (45%) had evidence of MVI. By univariate analysis, MVI was found to be statistically significantly associated with greater tumor size, gross classification, histological grade, and intrahepatic micrometastasis. Gross classification proved to be the only independent predictive factor for MVI by multiple logistic regression analysis. By multivariate analysis, cirrhosis and MVI were identified as independent risk factors for recurrence-free survival. The 5-year recurrence-free survival rates for patients with and without MVI were 20.8% and 52.6%, respectively. By multivariate analysis, the number of tumors, presence of MVI, and intrahepatic micrometastasis were identified as independent predictors of disease-specific survival. The 5-year disease-specific survival rates for patients with and without MVI were 59.3% and 92.0%, respectively. The presence of MVI was the most important risk factor affecting recurrence and survival in HCC patients after curative resection. Furthermore, this study showed that gross classification of HCC can be very helpful in predicting the presence of MVI.