Treatment of HCC in Patients Awaiting Liver Transplantation
Liver transplantation (LT) is the treatment of choice for many patients with unresectable hepatocellular carcinoma (HCC), but long waiting time due to the shortage of donor organs can result in tumor progression and drop-out from LT candidacy. Furthermore, even in candidates meeting the restrictive Milan criteria there is risk of HCC recurrence; this risk rises significantly when patients with more advanced HCC are included. In an effort to address these issues, treatment of HCC in patients awaiting LT has become widespread practice. In this review the various modalities employed in the pre-LT setting are presented, and the evidence for benefit with regard to (1) improvement of post-LT survival, (2) down-staging of advanced HCC to within Milan criteria and (3) preventing waiting list drop-out is considered. Chemoembolization, radiofrequency ablation and ethanol injection all have well-documented antitumor activity; however, there is no high level evidence that waiting list HCC treatment with these modalities is effective in achieving any of the three above-mentioned aims. Nevertheless, particularly in the United States, where continued waiting list priority depends on maintaining HCC within Milan criteria, use of nonsurgical HCC treatment will likely continue in an effort to forestall tumor progression and waiting list drop-out.

Liver transplantation (LT) has emerged as the primary treatment for unresectable small HCC, with a low rate of recurrence and excellent long-term survival in candidates selected according to the Milan criteria (1 nodule ≤5 cm, 2–3 nodules all ≤3 cm). Because of increasing demand in the face of a relatively fixed supply of donor organs, waiting time for LT has progressively lengthened, and despite priority for HCC within the Milan criteria a significant rate of drop-out from the waiting list due to tumor progression reduces overall survival of LT for HCC on an intention-to-treat basis. Treatment of HCC in patients awaiting LT has become commonplace, primarily in an effort to forestall tumor progression and drop out but also with the purpose of decreasing post-LT HCC recurrence or to downstage HCC that is beyond the Milan criteria at initial presentation. This review examines the various modalities employed to treat HCC in LT candidates and the evidence that these treatments effectively serve their intended purposes.