Atezolizumab Plus Bevacizumab Alone or Combined with External Beam Radiotherapy for HCC with Macrovascular Invasion

Inclusion Criteria: * Older than 19 years of age, lower than 80 years of age * Child-Pugh class A hepatic function * Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0-1 * Patients with HCC \[diagnosed according to AASLD guidelines\] invading the intrahepatic vascular system * No prior systemic therapy for HCC * At least one measurable HCC lesion with ≥ 1cm diameter * Adequate hematologic and organ function * Hemoglobin ≥ 9.0 g/dL * Absolute neutrophil count ≥ 1,000 /mm3 * Platelet ≥ 50,000/ mm3 without transfusion * Total bilirubin ≤ 2.5 mg/dL Exclusion Criteria: * Treatment history of prior systemic treatment of HCC * Liver transplant recipients * Patients with peptic ulcer, untreated or incompletely treated varices with bleeding or high-risk for bleeding * Any serious illness (e.g., active infection or inflammatory condition) or uncontrolled severe medical comorbidity * A history of treated malignancy (other than HCC) is allowable if the patient's malignancy has been in complete remission, off chemotherapy and without additional surgical intervention, during the preceding two years * Abdominal/pelvic radiotherapy within 28 days prior to initiation of study treatment, except palliative radiotherapy to bone lesions within 7 days prior to initiation of study treatment