Criteria for liver transplantation for HCC: what should the limits be?

Liver transplantation is a well-established treatment in a subset of patients with cirrhosis and hepatocellular carcinoma. The Milan criteria (single nodule up to 5 cm, up to three nodules none larger than 3 cm, with no evidence of extrahepatic spread or macrovascular invasion) have been traditionally accepted as standard of care. However, some groups have proposed that these criteria are too restrictive, and exclude some patients from transplantation who might benefit from this procedure. Transplanting patients with tumors beyond the established criteria falls into two categories, those whose tumors are beyond the Milan criteria at presentation without the use of treatment prior to transplantation (expanded criteria), and those in whom treatment allows the Milan Criteria to be fulfilled (down-staging). Currently, however, there is no international consensus regarding these approaches in clinical practice. The purpose of this systematic review is to clarify this debate through a critical analysis of available data. Finally, some comments on predictive factors apart from morphological characteristics are also addressed.