Transarterial radioembolization versus atezolizumab-bevacizumab for the treatment of hepatocellular carcinoma with portal vein tumor thrombosis

Purpose: The purpose of this study was to compare transarterial radioembolization (TARE) and atezolizumab plus bevacizumab (Atezo/Bev) in treatment-naïve patients with hepatocellular carcinoma (HCC) and portal vein tumor thrombosis (PVTT) without extrahepatic metastasis. Material and methods: This multicenter retrospective study evaluated 213 patients initially treated with TARE or Atezo/Bev between 2016 and 2023. The primary outcome was overall survival, and the secondary outcomes were progression-free survival, objective response rate, and safety. Baseline characteristics were adjusted using inverse probability treatment weighting or propensity score matching. Results: Deaths occurred in 36 out of 125 patients (28.8 %) in the TARE group and 57 out of 88 patients (64.8 %) in the Atezo/Bev group. The median overall survival was significantly longer in the TARE group (27.5 months) than in the Atezo/Bev group (8.6 months) (P < 0.01), consistent across analyses before matching (hazard ratio [HR], 0.38; 95% confidence interval [CI]: 0.25–0.58; P < 0.01), after inverse probability treatment weighting (HR, 0.49; 95 % CI: 0.28–0.85; P = 0.01), and after propensity score matching (HR, 0.40; 95% CI: 0.22–0.74; P < 0.01). In the PVTT subgroup involving segmental to lobar branches (Vp1–3), TARE demonstrated prolonged overall survival (HR, 0.36; 95 % CI: 0.20–0.63; P < 0.01), with no significant difference in patients with Vp4. The TARE and Atezo/Bev groups exhibited similar progression-free survival. No significant differences in objective response rate were found between TARE group (22.2–30.9 %) and Atezo/Bev group (30.6–30.9 %). Adverse events were less frequent in the TARE group than in the Atezo/Bev group. The incidence of grade ≥ 2 ascites and variceal bleeding were significantly lower in the TARE group (12.0 % and 1.7 %, respectively) than in the Atezo/Bev group (20.5 % and 8 %, respectively) (both P < 0.05). No significant differences in Child–Pugh score aggravation of ≥ 2 were observed between the TARE group (14.4 %) and the Atezo/Bev group (25 %) (P = 0.08). Conclusion: For patients with preserved liver function and locally advanced HCC involving segmental or lobar PVTT, TARE may be preferable to Atezo/Bev.