The combination therapy group includes patients with hepatocellular carcinoma and extrahepatic metastases who receive PD-1 inhibitor therapy (selected based on individual patient assessment and shared decision-making) alongside 125I radioactive seed implantation targeting their extrahepatic metastatic lesions. The intervention involves percutaneous implantation of 125I seeds into accessible metastases under imaging guidance to deliver localized radiation, complemented by systemic PD-1 inhibitor administration according to standard protocols. Patients undergo regular follow-ups to monitor treatment response (e.g., tumor size, pain scores), assess safety through laboratory and imaging evaluations, and manage comorbidities (such as hepatitis B virus infection or treatment-related adverse events) to ensure personalized, comprehensive care throughout the treatment course.

The PD-1 single-agent group includes patients with hepatocellular carcinoma and extrahepatic metastases who receive PD-1 inhibitor therapy selected through shared decision-making based on their individual clinical status, tumor characteristics, and treatment preferences. The intervention involves systemic administration of PD-1 inhibitors (e.g., pembrolizumab, nivolumab) according to standard oncological protocols, with dose and treatment schedule tailored to guidelines and patient tolerance. Patients in this group undergo regular follow-ups to assess treatment response (e.g., tumor progression via imaging, serum AFP levels), monitor safety through laboratory evaluations (blood counts, liver/kidney function), and manage comorbidities-such as chronic hepatitis B virus infection requiring antiviral prophylaxis or immune-related adverse events (e.g., pneumonitis, colitis)-to ensure safe and effective care throughout the treatment course.

125I seed implantation

It is the time interval from the start of treatment (initiation of PD - 1 inhibitor therapy or combination treatment) to the occurrence of tumor progression (defined by imaging criteria such as RECIST) or death from any cause, whichever comes first. Tumor progression includes the development of new lesions, increase in the size of existing lesions, or clinical deterioration indicative of disease advancement.

The length of time from either the start of treatment or diagnosis until the death of the patient from any cause.