Radiotherapy Delays Second-line Drug Therapy for Oligo Progressive Primary Liver Cancer

Inclusion Criteria: * Obtain written informed consent before implementing any trial-related procedures. * Male or female, aged 18 years or older, and 75 years or younger. * Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0-1. * Histological or cytological confirmation of primary hepatocellular carcinoma (HCC), or diagnosed according to the Clinical Diagnosis and Treatment Guidelines for Primary - Liver Cancer (2019 edition) issued by the National Health Commission of the People's Republic of China. * Tumor staged as BCLC stage C; patients have ≤5 lesions (≤3 affected organs) with oligometastasis or oligoprogression. * Liver function assessed by Child-Pugh score ≤7 points. * Availability of tumor samples for biomarker assessment. * Stable disease with systemic therapy for ≥3 months and an anticipated survival period of ≥6 months. Exclusion Criteria: * Diagnosis of malignancy other than liver cancer within 3 years before enrollment (excluding curatively treated basal cell carcinoma, squamous cell carcinoma of the skin, and/or in situ carcinoma). * Currently participating in interventional clinical research treatment, or received other investigational drugs or investigational device therapy within the past 4 weeks before enrollment. * Received traditional Chinese medicine or immunomodulatory drugs with anti-tumor indications within 2 weeks before enrollment (including thymosin, interferon, interleukin, except for local use to control pleural effusion). * Experienced active autoimmune diseases requiring systemic treatment (such as disease-modifying drugs, corticosteroids, or immunosuppressive agents) within 2 years before enrollment. Alternative therapies (such as thyroid hormone, insulin, or physiological glucocorticoids used for adrenal or pituitary insufficiency) are not considered systemic treatment. * Received radiotherapy within 2 weeks before enrollment. * HIV + * Active untreated hepatitis B (defined as HBsAg positive with HBV-DNA copy number exceeding the upper limit of normal value in the laboratory of the participating center). * Pregnant or lactating women.