Prospective Evaluation of a Locked Risk-Stratified Surveillance Strategy for Extrahepatic Metastasis in Hepatocellular Carcinoma

Inclusion Criteria

Inclusion Criteria: * Age ≥ 18 years. * Diagnosis of hepatocellular carcinoma (HCC) confirmed by histopathology or accepted radiologic criteria per international guidelines. * No evidence of extrahepatic metastasis at baseline evaluation. * Receiving standard-of-care management with planned longitudinal follow-up in routine clinical practice. * Availability of baseline clinical and imaging data required for risk assessment using the pre-specified machine learning model. * Ability to provide written informed consent, or inclusion under ethics committee-approved procedures. Exclusion Criteria: * Confirmed extrahepatic metastasis at enrollment (baseline). * History of other active malignancy within the past 5 years, except adequately treated non-melanoma skin cancer or in situ carcinoma. * Incomplete baseline clinical information that precludes model-based risk assessment. * Expected survival \< 3 months due to severe comorbidities. * Participation in an interventional clinical trial that may substantially alter follow-up strategy or metastasis assessment.