A System of Classifying Microvascular Invasion to Predict Outcome After Resection in Patients With Hepatocellular Carcinoma

Abstract

Background & Aims Hepatocellular carcinoma (HCC) recurs in approximately 70% of cases after resection. Vascular invasion by tumor cells can be classified as gross or microscopic (mVI) and is a risk factor for recurrence. We examined a large cohort of patients with HCC that were treated by resection to identify features of microvascular invasion that correlated with recurrence and survival. Methods We reviewed the records of all HCC resections performed at the Mount Sinai School of Medicine between January 1990 and March 2006 to identify those with mVI, established by histological analysis. The numbers and sizes of vessels invaded, invasion of a vessel with a muscular wall, distance from the tumor, and satellite nodules were recorded. Results Of the 384 patients that underwent resection for HCC, 131 (34.1%) met the entry criteria. The median follow-up period was 28.9 mo. There were 68 recurrences and 54 deaths. In multivariate analysis, invasion of a vessel with a muscular wall predicted recurrence (hazard ratio 1.8, P=0.02); invasion of a vessel with a muscular wall (hazard ratio=2.2, P=0.018) and invasion of a vessel that was more than 1 cm from the tumor (hazard ratio=2.1, P=0.015) predicted survival. A risk score that assigned point for the presence of each variable was correlated with recurrence (p=0.028) and survival (p<0.0001). Conclusion A novel classification system that includes invasion of a vessel with a muscular wall and invasion of a vessel that is more than 1 cm from the tumor can accurately predict risk of recurrence and survival of patients with mVI after HCC resection.