Impact of ISO score on oncological outcomes and survival in liver transplant candidates with hepatocellular carcinoma

Introduction Liver transplantation (LT) is the most efficacious curative treatment for hepatocellular carcinoma (HCC) patients. The waiting list (WL) prioritization criteria determine patient outcomes. Since 2015, the Italian Score for Organ Allocation (ISO) has been used in Italy to prioritize patients on the WL, introducing a specific policy for HCC. AIM To assess the impact of ISO-score on WL dropout, HCC recurrence, and patient survival in LT candidates with HCC. Materials and Methods We retrospectively analyzed all consecutive LT candidates with HCC at our Hospital from 2013 to 2020, comparing the impact on different outcomes in 2 groups: those patients prioritized before (group A, 2013-2015) and after (group B, 2016-2020) ISO score implementation. Results During the study period, 378 LT candidates with HCC were included: 261 patients underwent LT, 42 patients (11%) died before LT, and 57 patients (15%) were removed for HCC progression, during a median follow-up of 49 months. The intention-to-treat (ITT)-survival rates at 1- and 3-years were significantly lower in group A compared to group B (85% and 71% vs 89% and 85%, respectively, p=0.009). HCC recurrence rate at 3 years was significantly higher in group A compared to group B (19.5% vs. 8%, respectively, p=0.008) with similar waiting time in the two groups (median: 6 months, IQR 2-14). The dropout rate was not significantly different in the two groups (30% group A vs 25% group B, p=ns). At the same time, the disease-free survival 3 years after LT was significantly lower in group A vs group B (80% vs 92%, respectively, p=0.009). Explant pathology and AFP levels at LT were comparable in the two groups. Conclusion Implementing ISO score improved ITT-survival of LT candidates with HCC in a single center cohort. This improvement seems mainly related to a lower post-LT HCC recurrence rate than to a significant change in dropout rates.