Outcomes of Y90-radioembolization as downstaging to liver transplantation in patients with hepatocellular carcinoma and tumoral portal vein thrombosis

BACKGROUND AND AIMS: Hepatocellular carcinoma (HCC) with tumoral portal vein thrombosis (PVTT) is considered a contraindication to liver transplantation (LT). Transarterial radioembolization (TARE) may induce sustained regression of PVTT and achieve downstaging in selected patients, potentially enabling LT. The aim of this study is to assess post-LT oncological and survival outcomes in patients with HCC and PVTT who were successfully downstaged with TARE. APPROACH AND RESULTS: Consecutive patients with HCC and PVTT treated with TARE (2010-2023) at 5 Italian transplant centers were included. Successful downstaging required a sustained radiological response for at least 6 months with a complete or partial response of the PVTT component, together with fulfillment of center-specific morphological criteria and AFP thresholds. Survival analyses were conducted for the overall cohort from TARE and the transplanted patients. Among downstaged patients, cancer-related death according to transplant status was assessed using competing-risk analysis. Among 240 patients, 61 (25.4%) achieved sustained downstaging after TARE, and 37 patients (15.4%) eventually underwent LT. In competing-risk analysis, LT was associated with a lower risk of cancer-related death (60-month cumulative incidence: 15.8% vs. 45.2%; sHR 0.221, 95% CI 0.071-0.683; p =0.0087). The median time from TARE to LT was 17 months. In the 37 transplanted patients, post-LT 3-year and 5-year OS and RFS were 67.2%/61.6% and 79.3%/79.3%, respectively. Pathology showed complete tumor necrosis in 56.7% explants. CONCLUSIONS: Radioembolization downstaged ~1 in 4 PVTT patients to transplant eligibility. After downstaging, LT conferred markedly superior oncological outcomes. TARE in PVTT associated with HCC represents a valid, transplant-oriented option with a distinct efficacy profile.