Significant Reduction in Posttransplant Hepatocellular Carcinoma Recurrence in the Post 6-Mo Waiting Policy Era.

BACKGROUND: In 2015, the United Network for Organ Sharing implemented a policy introducing a 6-mo waiting period before granting model for end-stage liver disease exception points to liver transplant (LT) candidates with hepatocellular carcinoma (HCC). This study analyzes the policy impact on post-LT HCC recurrence. METHODS: This was a United Network for Organ Sharing retrospective cohort study of patients with HCC who underwent LT from January 1, 2010, to May 31, 2019. HCC-specific data included alpha-fetoprotein, tumor characteristics, locoregional therapy (LRT), and explant data used to calculate the Risk Estimation of Tumor Recurrence After Transplant score. The primary exposure was pre-/post-policy era, divided on October 8, 2015. Survival analysis techniques were used to evaluate the unadjusted and sequentially adjusted association between policy era and HCC recurrence, accounting for competing risks. RESULTS: A total of 7940 patients were included, 5879 (74.0%) pre-policy era and 2061 (26.0%) post-policy era. Post-policy patients were older, received more LRT, and had lower alpha-fetoprotein levels and smaller tumor sizes at transplant. Incidence rates of HCC recurrence were 19.8 and 13.7 events per 1000 person-years for pre- and post-policy eras, respectively. Post-policy era was associated with an unadjusted 35% reduction in the risk of HCC recurrence (P < 0.001). After adjusting for recipient, donor, and tumor characteristics at listing this association remained (subhazard ratio 0.69; 95% confidence interval, 0.55-0.86; P = 0.001); however, after additionally adjusting for LRT episodes and Risk Estimation of Tumor Recurrence After Transplant score, there was no longer a statistically significant association (subhazard ratio 0.77; 95% confidence interval, 0.59-1.00; P = 0.054). CONCLUSIONS: We observed a significant reduction in post-LT HCC recurrence after policy implementation. This may be due to waitlist selection of healthier patients, increased LRT utilization, and potential selection of favorable tumor biology.