**4.3 Criteria for liver transplantation**

The field of liver transplantation has gone through many transformations since its early days. Over time this surgical procedure evolved from being a treatment option mostly for individuals with irreversible severe liver dysfunction from any acute or chronic illness to also a providing a proven curative alternative for patients with early stage hepatocellular carcinoma. Currently, the success rate and outcomes seen in this subset of liver transplant recipients is similar to that of recipients who underwent transplantation for indications other than hepatoma. This is in great part due to the knowledge and understanding obtained from outstanding clinical studies published over the last 20 years (Bismuth, 1993; Figueras, 1997; Iwatsuki, 1991; Mazzaferro, 1996; Tan, 1995). These studies have paved the way to the creation of the criteria for liver transplantation and guidelines that are used today.

#### **4.3.1 Milan criteria**

The Milan criteria are at the present time the accepted and recommended measure to determine the liver transplantation candidacy of patients with hepatocellular carcinoma. This criteria described in a landmark paper by Mazzaferro and colleagues, demonstrated that in patients with cirrhosis and a single tumor up to 5 centimeters, or up to three lesions none larger than 3 centimeters, and with no evidence of extrahepatic spread or macrovascular invasion the 4-year post-transplant survival was similar to that of recipients transplanted for reasons other than liver cancer (Mazzaferro, 1996). These findings of greater than 70% survival rate gave a second chance to the previously aborted efforts of transplanting cirrhotic patients with primary liver cancer. The United Network for Organ Sharing endorses these criteria, and adopted them for their liver allocation policies of patients with hepatocellular carcinoma (UNOS, 2010). Despite being validated by many studies, some believe that the Milan criteria are too restrictive and exclude a subset of patients with hepatoma that could have excellent outcomes if were transplanted (M.F. Silva & Sherman, 2011).
