UNOS Down-Staging Criteria for Liver Transplantation of Hepatocellular Carcinoma: Systematic Review and Meta-Analysis of 25 Studies.

BACKGROUND & AIMS: Down-staging is commonly used to select patients with hepatocellular carcinoma (HCC) beyond Milan criteria (MC) for liver transplantation (LT), but outcomes are heterogenous. We aimed to estimate pooled down-staging success rates, HCC recurrence, and overall survival (OS), stratified by criteria used for baseline tumor burden.

METHODS

We searched Pubmed and EMBASE databases from inception until August 2021 for studies reporting down-staging success (reduction of tumor burden to within MC) and outcomes of adult HCC patients. In addition, we performed a pooled analysis using reconstructed individual participant data to obtain robust estimates for OS.

RESULTS

We screened 1059 articles and included 25 articles involving 3997 patients. Overall, 55.16% (45.49%-64.46%) underwent successful down-staging, and 31.52% (24.03%-40.11%) received LT (by intention-to-treat analysis [ITT]). Among patients who received LT, 16.01% (11.80%-21.37%) developed HCC recurrence. Comparing studies that used the United Network for Organ Sharing Down-Staging (UNOS-DS) criteria versus studies beyond UNOS-DS or did not specify criteria, down-staging success (by ITT) was 83.21% versus 45.93%, P < .001; the proportion who received LT (by ITT) was 48.61% vs 28.60%, P = .030; and HCC recurrence (among patients who received LT) occurred in 9.06% versus 20.42%, P < .001. Among studies that used UNOS-DS criteria, ITT 1- and 5-year OS from the initiation of down-staging treatment was 86% and 58%, respectively, whereas 1- and 5-year post-LT OS was 94% and 74%, respectively.

CONCLUSIONS

Among studies that adhered to UNOS-DS criteria, down-staging was successful in four-fifths of patients, >50% received LT, and post-LT outcomes were excellent. These data provide clinical validation for the utilization of UNOS-DS criteria.