Small graft size and hepatocellular carcinoma outcomes in living donor liver transplantation: a retrospective multicentric cohort study.

INTRODUCTION:This study examined associations between the graft-to-recipient weight ratio (GRWR) for adult-to-adult living donor liver transplantation (LDLT) and HCC outcomes. MATERIALS AND METHODS:Data from patients in the Korean Organ Transplantation Registry who underwent LDLT for HCC from 2014-2021 were retrospectively reviewed. Patients were categorized using the cutoff GRWR for HCC recurrence determined by an adjusted cubic spline (GRWR<0.7% vs. GRWR≥0.7%). Recurrence-free survival (RFS) and HCC recurrence were analyzed in the entire and a 1:5 propensity-matched cohort. RESULTS:The eligible cohort consisted of 2005 LDLT recipients (GRWR<0.7 [n=59] vs. GRWR≥0.7 [n=1946]). In the entire cohort, 5-year RFS was significantly lower in the GRWR<0.7 than in the GRWR≥0.7 group (66.7% vs. 76.7%, P=0.019), although HCC recurrence was not different between groups (77.1% vs. 80.7%, P=0.234). This trend was similar in the matched cohort (P=0.014 for RFS and P=0.096 for HCC recurrence). In multivariable analyses, GRWR<0.7 was an independent risk factor for RFS (adjusted HR [aHR] 1.89, P=0.012), but the result was marginal for HCC recurrence (aHR 1.61, P=0.066). In the pretransplant tumor burden subgroup analysis, GRWR<0.7 was a significant risk factor for both RFS and HCC recurrence only for tumors exceeding the Milan criteria (aHR 3.10, P<0.001 for RFS; aHR 2.92, P=0.003 for HCC recurrence) or with MoRAL scores in the fourth quartile (aHR 3.33, P<0.001 for RFS; aHR 2.61, P=0.019 for HCC recurrence). CONCLUSIONS:A GRWR<0.7 potentially leads to lower RFS and higher HCC recurrence after LDLT when the pretransplant tumor burden is high.