Histologic Grade and Mitotic Index as Predictors of Microvascular Invasion in Hepatocellular Carcinoma.

Objectives: Microvascular invasion is a well-known risk factor for hepatocellular carcinoma recurrence and mortality after hepatic resection and liver transplant. We sought to determine the clinico-pathological predictive factors associated with microvascular invasion.

Materials And Methods: We studied all patients who had undergone liver transplant because of hepatocellular carcinoma between July 2001 and December 2010 at our institution. Laboratory tests, clinical, and demographic data were obtained. Histopathological hematoxylin and eosin specimens were performed by a single liver pathologist.

Results: During the study, 107 patients had LT because of HCC and they were selected for this investigation: 76 were men (71%) and 31 women (29%) (mean age, 56.8 ± 8.7 y). It was not possible to retrieve histologic samples from 5 patients; therefore, the final studied analysis was 102 individuals. Tumor recurrence rate was 12.9%. One-, three- and five-year overall survivals were 75.0%, 71.4%, and 67.5%. Mitotic index, histologic grade, tumor architecture, alpha-fetoprotein, and tumor fibrosis were associated with microvascular invasion on univariate analysis. Significant independent predictors of microvascular invasion on logistic regression analysis were histologic grade and mitotic index (P < .001; odds ratio, 3.16; 95% confidence interval, 1.525-4.156, and P = .046; odds ratio, 2.56; 95% confidence interval, 1.061-6.451).

Conclusions: Mitotic index and histologic grade are significant predictors of microvascular invasion. No other risk factor was identified in the logistic regression. As both pathological characteristics may be assessed by liver biopsy, these results highlight the importance of discussing pretransplant liver biopsy to access prognosis and define treatment modalities in the setting of liver transplant.