Microvascular Invasion in Hepatocellular Carcinoma and Liver Transplant.

OBJECTIVES Curative therapy for hepatocellular carcinoma is liver transplant. To date, the Milan Criteria remain the best pretransplant clinical surrogate for tumor behavior and overall prognosis. Microvascular invasion portends a poor prognosis; however, it is often undetectable before transplant. Furthermore, its pretransplant indicators are not well established. In this study, we investigated the presurgical and pathologic predictors of microvascular invasion in patients with hepatocellular carcinoma. MATERIALS AND METHODS Between August 2000 and August 2013, 156 liver transplants were performed for hepatocellular carcinoma at the Johns Hopkins Medical Center. Information on clinical characteristics and pathology data, including microvascular invasion, were available for 107 patients on liver explants. Logistic regression was used to assess the effects of Milan Criteria, alpha-fetoprotein, tumor differentiation, and multilobar involvement on the presence of microvascular invasion on explant pathology. RESULTS In 107 patients, 24 (22%) had microvascular invasion on pathology. In patients with microvascular invasion, 41% were outside of Milan Criteria versus 19.3% of patients within but without microvascular invasion. In patients with microvascular invasion, the rate of poor differentiation and alpha-fetoprotein level > 1000 ng/mL were more common than in patients without microvascular invasion; however, on univariate and multivariable analyses, Milan Criteria, alphafetoprotein level, multilobar involvement, and differentiation did not reach statistical significance in predicting microvascular invasion on pathology. CONCLUSIONS In this study, potential predictors of microvascular invasion, including Milan Criteria, alphafetoprotein level, tumor differentiation, and multilobar involvement, were not predictive. Preoperative prediction of microvascular invasion remains a challenge, suggesting the need for future studies.