The presence of bilobar tumor should be considered as a new limit for transplantation beyond the Milan criteria?

Abstract

BACKGROUND: An imprecise estimate of the tumor's aggressiveness of the hepatocellular carcinoma especially in transplanted patients beyond the Milan criteria has a poor outcome, although a more reliable criteria including microscopic vascular invasion is difficult to be established before transplantation. AIM: To examine a cohort of patients with hepatocellular carcinoma undergoing liver transplantation to evaluate the preoperative predicting factors for microscopic vascular invasion. METHODS: A series of 46 consecutive cirrhotic patients with hepatocellular carcinoma undergoing transplantation based on Milan criteria or similar criteria in a single center were enrolled between 1993 and 2007. The survival was calculated using Kaplan-Meyer's method and a multivariate Cox regression was performed to evaluate survival and factors related to microscopic vascular invasion. RESULTS: Multifocal tumors were present in 39%. Microvascular invasion, tumor relapses and hepatocellular carcinoma beyond the Milan criteria were identified in 33%, 13% and 33%, respectively. Overall 1-, 3-, and 5-year actuarial patient survival rates were 64%, 59% and 45% respectively. Patients who exceeded the Milan criteria had a higher incidence of microscopic vascular invasion and bilobar tumor compared to those who met the Milan criteria (53% vs. 23% and 80% vs. 19%; p<0.05, respectively). After multivariate analysis, the variable identified as independent risk factor for microscopic vascular invasion was the presence of bilobar tumor (hazard ratio, 3.67; 95% confidence interval, 1.01 to 13.34; p<0.05). CONCLUSIONS: The presence of a bilobar tumor is more frequent in hepatocellular carcinoma beyond the Milan criteria and it is an independent predictive factor of a high risk of microscopic vascular invasion. The presence of bilobar tumor in hepatocellular carcinoma beyond the Milan criteria could be used as selection criteria to estimate the risk of hepatocellular carcinoma recurrence, at least until large randomized studies becomes available.