Background and aims: Liver transplantation (OLT) for hepatocellular carcinoma (HCC) improves patient survival when tumor size and number are limited according to the Milan criteria. However, the impact of tumor size vs. the number of lesions for tumor recurrence after OLT is unclear. Microvascular invasion appears to be a significant risk factor for tumor recurrence. Therefore, it was the aim of this study to investigate tumor differentiation and microvascular invasion in relation to tumor number and size and their impact on survival after transplantation.
Patients and methods: In 97 adult HCC patients who underwent OLT between June 1985 and December 2005 the incidence of microvascular invasion, tumor differentiation, and the number and size of tumor lesions were analyzed retrospectively. Their impact on survival was studied by multivariate analysis.
Results: Microvascular invasion was the only independent negative predictor of survival after OLT for HCC (p = 0.025). Tumor size > 5 cm was predictive for microvascular invasion (p = 0.007). In contrast, tumor number did not affect the incidence of microvascular invasion or cumulative survival.
Conclusion: The size of the largest HCC lesion, but not the number of tumors, determined microvascular invasion, a predictor of the outcome following OLT for HCC. Thus, the number of HCC lesions should not be applied to patient selection prior to OLT. These data support the extension of the Milan criteria for the selection of HCC patients for OLT with regard to tumor number, but not tumor size.