Liver Allocation Policies in the USA: Past, Present, and the Future.

Identifying the optimal allocation policy with regard to hepatocellular carcinoma has been a persistent and evolving challenge. The current criteria for LT for HCC endorsed by the United Network of Organ Sharing (UNOS) are based on the Milan Criteria: a solitary tumor < 5 cm, or maximum of three tumors ≤ 3 cm each, without vascular invasion or evidence of extrahepatic spread. Contraindications to HCC exception points include: stage 1 HCC, ruptured HCC, extrahepatic HCC, and main portal or hepatic vein HCC invasion. Based upon projected waitlist dropout rates due to tumor growth, patients with HCC are assigned MELD standardized exception points. In addition to tumor size and number, AFP levels are an important predictor of recurrence of HCC following liver transplantation. Standardized exception points for HCC patients are not awarded to patients with AFP levels > 1000 ng/mL that do not decrease to < 500 ng/mL with treatment. Appeals for MELD exception points for patients with HCC vary widely between UNOS regions, with success of nonstandardized exception point appeals varying from 3.1 to 21% between regions. In an effort to make prioritization for HCC more consistent, a national liver review board (NLRB)is being convened that will focus on developing a national guidance for assessing common requests and addressing exception points, including for HCC.