Combination of SBRT and Immunotherapy in Small Hepatocellular Carcinoma (HSBRT2402)

Inclusion Criteria: 1. Histologically confirmed hepatocellular carcinoma or diagnosed by American Association for the Study of Liver Disease criteria; 2. Presence of recurrent or residual HCC lesions without vascular invasion or extrahepatic metastasis confirmed by CT or MRI, the sum of the maximum diameter of lesions ≤5 cm, total number of lesions were ≤2, and at least one of which is measurable according to the RECIST 1.1 Criteria; 3. Previous molecular targeted therapy or intravenous chemotherapy is allowed, but the interval of drug withdrawal was at least 6 months prior to protocol therapy; 4. Age at diagnosis 18 to 75 years; 5. Eastern Cooperative Oncology Group performance status ≤ 2 6. Child-Pugh class A liver function; 7. Normal liver volume greater than 700 ml; 8. Estimated life expectancy ≥24 weeks; 9. The function of important organs meets the following requirements: a. white blood cell count (WBC) ≥ 3.0×109/L, absolute neutrophil count (ANC) ≥ 1.5×109/L; b. platelets ≥ 50×109/L; c. hemoglobin ≥ 9g/dL; d. serum albumin ≥ 2.8g/dL; e. total bilirubin ≤ 1.5×ULN, ALT, AST and/or AKP ≤ 2.5×ULN; f. serum creatinine ≤ 1.5×ULN or creatinine clearance rate \>60 mL/min; 10. Ability to understand the study and sign informed consent. Exclusion Criteria: 1. Patients who have previously been treated with immune checkpoint inhibitors; 2. Patients with extrahepatic metastasis disease; 3. A history of abdominal radiotherapy; 4. Known or suspected allergy or hypersensitivity to monoclonal antibodies; 5. Patients who have a preexisting or coexisting bleeding disorder; 6. Female patients who are pregnant or lactating; 7. Inability to provide informed consent due to psychological, familial, social and other factors; 8. A history of malignancies other than hepatocellular carcinoma before enrollment, excluding non-melanoma skin cancer, in situ cervical cancer, or cured early prostate cancer; 9. A history of diabetes for more than 10 years and poorly controlled blood glucose levels; 10. Patients who cannot tolerate radiotherapy due to severe cardiac, lung, liver or kidney dysfunction, or hematopoietic disease or cachexia; 11. Active autoimmune diseases, a history of autoimmune diseases (including but not limited to these diseases or syndromes, such as colitis, hepatitis, hyperthyroidism), a history of immunodeficiency (including a positive HIV test result), or other acquired or congenital immunodeficiency diseases, a history of organ transplantation or allogeneic bone marrow transplantation; 12. A history of interstitial lung disease or non-infectious pneumonia; 13. A history of active pulmonary tuberculosis infection within 1 year or a history of active pulmonary tuberculosis infection more than 1 year ago but without formal anti-tuberculosis treatment; 14. Presence of active hepatitis B (HBV DNA ≥ 2000 IU/mL or 104 copies/mL), hepatitis C (positive for hepatitis C antibody, and HCV-RNA levels higher than the lower limit of the assay); 15. Any unstable situation that may endanger the safety and compliance of patients.