Towards More Effective Liver Allocation Criteria for Hepatocellular Carcinoma: Tumor Response to Locoregional Therapy

Excerpt

Since the United Network of Organ Sharing (UNOS) implemented the Milan criteria in 2002 to assign listing priorities for liver transplantation in patients with hepatocellular carcinoma (HCC), the field of liver transplantation has actively searched for further refinements to optimize organ allocation for this indication.1 The success of the Milan criteria lies not only in its ability to stratify patients by their long-term outcomes after liver transplantation for HCC but in its ease of application: on preoperative cross-sectional imaging, patients with cirrhosis and a single tumor smaller than 5 cm or up to three tumors each smaller than 3 cm without macrovascular invasion or extrahepatic spread receive transplantation priority. Numerous studies have subsequently reported that liberalization of these thresholds on tumor size and number results in similar long-term outcomes and have begun to influence prioritization schemes; for example, the Transplantation Society of Australia and New Zealand has moved to using the University of California, San Francisco (UCSF) criteria, defined as a single tumor up to 6.5 cm in diameter or three tumors with total tumor diameter up to 8 cm.2 Application of either the Milan or UCSF criteria results in an appreciable HCC recurrence rate of approximately 10% at 5 years. That the liberalization of prioritization criteria can produce comparable long-term results but continues to result in a measurable rate of cancer recurrence indicates that there exist larger tumors which may have favorable biology and may be cured with transplantation, whereas some diminutive lesions may be biologically aggressive and have higher chance of recurrence after transplantation. The task at hand is to develop better indicators to select patients with lower likelihood of HCC recurrence after transplantation. …