Positron emission tomography/computed tomography in patients with hepatocellular carcinoma undergoing liver transplantation. Useful, necessary or irrelevant?

•PET has been correlated with size, degree of differentiation and microvascular invasion.•PET is an independent prognostic factor of survival.•PET could become a tool for decision-making in HCC outside the Milan criteria.•PET should be generalized in HCC patients who are candidates for OLT.

Hepatocellular Carcinoma (HCC) is an aggressive tumor entity, with the only curative options being surgical resection or orthotopic liver transplantation (OLT). The presence of one single tumor nodule of less than 5 centimeters diameter or a maximum of 3 nodules, with the largest of these not exceeding 3 centimeters (Milan criteria) constitute the clinical situation in which the best results for OLT in patients with HCC have been achieved. The survival of patients fulfilling the Milan criteria after transplantation is comparable to patients with similar tumor stages without cirrhosis, undergoing hepatic resection. The application of PET in oncology has become increasingly common in the last decade as it is a non-invasive tool that also gathers information about the degree of the biological aggressiveness of the tumor. The objective of this study was to perform a review of the literature, identifying the strengths and weaknesses of the PET as a prognostic tool in patients with HCC after OLT.