The present study aimed to assess the effectiveness of the combination treatment of Atezolizumab/Bevacizumab, transcatheter arterial chemoembolization (TACE) and I-125 Seeds Brachytherapy (TACE-AB-I) in patients with advanced hepatocellular carcinoma (HCC) and portal vein tumor thrombosis (PVTT). The investigators confirmed that the combination therapy yielded better survival data than the combined administration of Atezolizumab/Bevacizumab and TACE (TACE-AB) in patients with advanced HCC and Type I/II PVTT (Based on Cheng's PVTT classification).

This is a multicenter, open-label trial, randomized controlled to evaluate the efficacy and safety of TACE-AB-I compared with TACE-AB for the treatment of HCC with branch PVTT. 234 HCC patients with branch PVTT will be enrolled in this study. The Patients will be treated with TACE-AB-I or TACE-AB using a 1:1 randomization scheme. TACE will be performed for the patients after randomization. Atezolizumab/bevacizumab (1,200 mg atezolizumab plus 15 mg/kg bevacizumab intravenously every 3 weeks) will be started at 3-7 days after the first TACE and I-125 Seeds Brachytherapy and last until disease progresses, intolerable toxicity, withdrawal of informed consent, loss of follow-up, death, or other circumstances that require termination of treatment, whichever occurs first. For patients in the TACE-AB-I arm, iodion-125 seeds will be implanted into the PVTT (according to the pre-operative planning) under CT guidance within 3-7 days after the first TACE. TACE and iodion-125 seeds implantation can be repeated on demand during follow-up based on the evaluation of laboratory and imaging examination.

Inclusion Criteria:

• Age between18 and 75 years;
• Has a diagnosis of HCC confirmed by radiology, histology, or cytology;
• Type I PVTT or type II PVTT;
• Child-Pugh class A;
• Eastern Cooperative Group performance status (ECOG) score of 0-1;
• No prior systemic therapy for HCC.
• Adequate hematologic and end-organ function;
• At least one measurable intrahepatic target lesion.

Exclusion Criteria:

• Diffuse HCC;
• Cholangiocarcinoma, fibrolamellar, sarcomatoid hepatocellular carcinoma, and mixed hepatocellular/cholangiocarcinoma subtypes (confirmed by histology, or pathology) are not eligible;
• Evidence of extrahepatic spread (EHS);
• Any condition representing a contraindication to TACE or I-125 seeds brachytherapy as determined by the investigators;
• Evidence or history of bleeding diathesis or any hemorrhage or bleeding event >CTCAE grade 3 within 4 weeks prior to randomization;
• Active or history of autoimmune disease or immune deficiency;
• Untreated or incompletely treated esophageal and/or gastric varices with bleeding or high risk for bleeding;
• A prior bleeding event due to esophageal and/or gastric varices within 6 months prior to initiation of study treatment;
• Evidence of bleeding diathesis or significant coagulopathy;
• Pregnant or breastfeeding females;
• Significant cardiovascular disease;
• Severe infection, such as active tuberculosis;
• Serious medical comorbidities;
• History of organ or cells transplantation;
• History of other uncurable malignancies.

Plan to share IPD with collaborators.