Lenvatinib, Sintilimab Plus SIRT for Unresectable HCC

Inclusion Criteria: * Unresectable HCC (BCLC stage B/C) with diagnosis confirmed by histology/cytology or clinically * At least one measurable untreated lesion * Intrahepatic tumors can be treated with 1-2 session of SIRT * Child-Pugh score 5-7 * Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 or 1 * Life expectancy of at least 3 months * Patients with active hepatitis B are allowed, but they need to receive antiviral treatment to achieve a HBV DNA\<10\^3 IU/mL * Patients with hepatitis C need to finish the anti-HCV treatment Exclusion Criteria: * tumor extent ≥70% liver occupation * Tumor thrombus involving main portal vein or both the first left and right branch of portal vein * Vena cava invasion * Central nervous system metastasis * Metastatic disease that involves major airways or blood vessels * Patients who previously received hepatic arterial infusion chemotherapy (HAIC), transarterial chemoembolization (TACE), transarterial embolization (TAE), radiotherapy, systemic therapy, or immunotherapy for HCC * History of organ and cell transplantation * Prior esophageal and/or gastric varices bleeding * History of hepatic encephalopathy * Peripheral blood white blood cell count\<3×10\^9/L, platelet count\<50×10\^9/L * Prolongation of prothrombin time ≥ 4 seconds * Severe organ dysfunction (heart, lungs, kidneys) * History of malignancy other than HCC * HBsAg and anti-HCV antibody positive concurrently * Human immunodeficiency virus (HIV) infected