BITS-TO-HCC Study: HAIC+Iparomlimab/Tuvonralimab + Bevacizumab + SBRT for BCLC-C HCC With PVTT and/or Oligometastases

Inclusion Criteria: 1. Male or female patients aged between 18 and 70 years. 2. Unresectable HCC, BCLC Stage C according to the BCLC strategy-2025 update, with staging established via biopsy pathology and/or clinical diagnosis. 3. Child-Pugh class A without clinically significant hepatic decompensation; Eastern Cooperative Oncology Group (ECOG) performance status 0-1 4. Metastatic burden and SBRT eligibility * Extrahepatic oligometastatic disease defined as ≤3 involved organs with ≤5 total metastatic lesions * All intended intrahepatic and/or extrahepatic SBRT targets must satisfy protocol-specified target-coverage, liver reserve, and organ-at-risk (OAR) constraints within a composite 5-fraction plan 5. Prognosis \& measurable disease * Life expectancy ≥3 months * ≥1 measurable lesion (per RECIST 1.1): * Tumor: ≥10 mm (CT long axis) * Lymph node: ≥15 mm (CT short axis) 6. Prior therapy * Prior locoregional therapy permitted：radiofrequency ablation (RFA), TACE, or HAIC, provided that: * Documented radiographic progression or intolerance after the prior therapy * Washout ≥28 days * Treatment-related toxicities recovered to ≤Grade 1 (alopecia and peripheral neuropathy ≤Grade 2 allowed) 7. Laboratory and virologic requirements * Aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) ≤5 × upper limit of normal (ULN); total bilirubin ≤3 × ULN; serum albumin ≥28 g/L * Serum creatinine ≤1.5 × ULN or creatinine clearance ≥50 mL/min * Urine dipstick protein \<2+; if baseline dipstick proteinuria is ≥2+, 24-hour urinary protein must be \<1 g * International normalized ratio (INR) and activated partial thromboplastin time (aPTT) ≤1.5 × ULN Exclusion Criteria: 1. Histopathological exclusions * Mixed HCC subtypes: Fibrolamellar HCC or sarcomatoid HCC or cholangiocarcinoma components 2. Curative local therapy candidacy * Current candidacy for resection, liver transplant, or RFA 3. RT infeasibility * Prior radioembolization * Single liver tumor ≥15 cm or total intrahepatic tumor diameter ≥20 cm * more than 5 discrete intrahepatic parenchymal foci are present * direct tumor extension into the stomach, duodenum, small bowel, or large bowel * measurable common or main-branch biliary duct involvement * Prior liver radiotherapy that would result in excessive overlap with the planned treatment fields 4. Prior systemic therapies * Received targeted-immunotherapy for HCC (e.g., PD-(L)1 inhibitors + tyrosine kinase inhibitors (TKIs)) * Prior immunotherapy: anti-PD-(L)1/CTLA-4 or chimeric antigen receptor T-cell therapy 5. Hemorrhage/portal hypertension and hepatic decompensation risk * Variceal bleeding within 6 months. * Untreated or high-risk esophagogastric varices (e.g., grade ≥2 on endoscopy within 3 months) or other clinical evidence of portal hypertension with high bleeding risk per investigator. * Moderate or severe ascites * History of or active hepatic encephalopathy * History of hemoptysis (≥2.5 mL of bright red blood per episode) within 28 days before study treatment * Evidence of bleeding diathesis or significant coagulopathy * Current or recent (within 10 days before study treatment) use of aspirin (≥325 mg/day), dipyridamole, ticlopidine, clopidogrel, cilostazol, or therapeutic-dose oral/parenteral anticoagulants or thrombolytic agents 6. Allergy to any component of iparomlimab/tuvonralimab or bevacizumab 7. Comorbidities * Active autoimmune disease or a history of autoimmune or inflammatory disease that may relapse; exceptions include hypothyroidism controlled with hormone replacement only, controlled celiac disease, and skin disorders not requiring systemic treatment (e.g., vitiligo, psoriasis, or alopecia) * Any condition requiring systemic corticosteroids (\>10 mg/day prednisone or equivalent) or other immunosuppressive medication within 14 days before study treatment * Active or uncontrolled infection, including tuberculosis, or known HIV infection * Prior allogeneic stem cell transplantation or organ transplantation * Inadequately controlled hypertension, defined as systolic blood pressure ≥150 mmHg and/or diastolic blood pressure \>90 mmHg despite optimal medical management, or a history of hypertensive crisis or hypertensive encephalopathy * History within 6 months before study treatment of myocardial infarction, unstable angina, symptomatic heart failure (New York Heart Association class ≥II), cerebrovascular accident, transient ischemic attack, pulmonary embolism, deep vein thrombosis, or other serious thromboembolic events * Major surgical procedure within 28 days before study treatment, or serious, non-healing or dehiscing wound, active ulcer, or untreated bone fracture * History within 6 months before study treatment of gastrointestinal perforation, abdominal or tracheoesophageal fistula, or intra-abdominal abscess