Atezolizumab plus bevacizumab is the first-line treatment for patients with advanced hepatocellular carcinoma. However, the prognosis for high-risk hepatocellular carcinoma is still poor, with a median overall survival of 7.6 months. Hepatic arterial infusion chemotherapy of oxaliplatin, 5-fluorouracil and leucovorin is effective in large hepatocellular carcinoma or hepatocellular carcinoma with major portal vein tumor thrombus. Our previous showed that hepatic arterial infusion chemotherapy plus lenvatinib and toripalimab (programmed cell death protein-1 antibody) had a powerful anti-tumor effect for high-risk hepatocellular carcinoma, with a median overall survival of 18 months. Thus, the purpose of this study is to evaluate the efficacy and safety of hepatic arterial infusion chemotherapy of oxaliplatin, 5-fluorouracil and leucovorin plus atezolizumab plus bevacizumab for patients with high-risk hepatocellular carcinoma.

Inclusion Criteria:

• The diagnosis of HCC was based on the diagnostic criteria for HCC used by the European Association for the Study of the Liver (EASL)
• Patients must have at least one tumor lesion that can be accurately measured according to EASL criteria.
• Barcelona clinic liver cancer-stage C
• High risk disease: Vp-4 based on the Japanese standard, bile duct invasion, or tumor occupancy ≥50% of the liver
• Eastern Cooperative Oncology Group performance status of 0 to 2
• With no previous treatment
• No Cirrhosis or cirrhotic status of Child-Pugh class A only
• Not amendable to surgical resection ,local ablative therapy and any other cured treatment.
• The following laboratory parameters:

Hemoglobin ≥ 8.5 g/dL Total bilirubin ≤ 30mmol/L Serum albumin ≥ 32 g/L ASL and AST ≤ 5 x upper limit of normal Serum creatinine ≤ 1.5 x upper limit of normal INR ≤ 1.5 or PT/APTT within normal limits Absolute neutrophil count (ANC) >1,500/mm3

• Ability to understand the protocol and to agree to and sign a written informed consent document

Exclusion Criteria:

• Evidence of hepatic decompensation including ascites, gastrointestinal bleeding or hepatic encephalopathy
• Known history of HIV
• History of organ allograft
• Known or suspected allergy to the investigational agents or any agent given in association with this trial.
• Cardiac ventricular arrhythmias requiring anti-arrhythmic therapy
• Evidence of bleeding diathesis.
• Patients with clinically significant gastrointestinal bleeding within 30 days prior to study entry.
• Known central nervous system tumors including metastatic brain disease