Study Objective: To compare the efficacy and prognosis of systemic cancer therapy between TAF monotherapy and ETV plus TAF combination therapy in patients with unresectable, advanced hepatitis-B-related hepatocellular carcinoma (HBV-HCC).

Study Design: Prospective, interventional cohort study. Participants: Patients with histologically or radiologically confirmed unresectable, advanced HBV-HCC who are scheduled to receive immune-based systemic therapy at The Third Affiliated Hospital of Sun Yat-sen University. Detailed inclusion/exclusion criteria are provided below.

Intervention: Enrolled participants will be assigned to receive either TAF monotherapy or ETV combined with TAF for HBV suppression.

Primary Outcome: Overall survival (OS) at 24 months after initiation of systemic therapy, compared between the two HBV-treatment strategies.

Secondary Outcomes: Decline in HBV DNA and HBsAg levels at 1, 3, 12 and 24 months.

Sample Size: 120 HCC patients (60 per arm). Statistical Analysis: All analyses will be performed with SPSS. Continuous variables will be tested for normality (Shapiro-Wilk). Normally distributed data are presented as mean ± SD; non-normally distributed data as median (IQR). Twenty-four-month OS will be estimated by Kaplan-Meier curves and compared with a Cox proportional-hazards model adjusted for age, BCLC stage, AFP level, and ICI regimen. PFS will be compared using the log-rank test; ORR and HBV DNA undetectable rate will be compared with χ² tests. Inverse-probability-of-treatment weighting (IPTW) will address selection bias, and multiple imputation will handle missing data.

Inclusion Criteria:

• Age ≥ 18 years, positive HBsAg for ≥ 6 months, and HBV DNA ≥ 2,000 IU/mL within 2 weeks before enrollment;

  • Histologically or clinically confirmed unresectable or metastatic hepatocellular carcinoma, Child-Pugh class A or B, ECOG performance status 0-1, and scheduled to receive systemic immunotherapy in the Department of Infectious Diseases, The Third Affiliated Hospital of Sun Yat-sen University;

    • At least one measurable lesion that has either not undergone local therapy or has progressed after local therapy, as defined by modified RECIST (mRECIST); ④ Estimated life expectancy ≥ 12 weeks; ⑤ Signed informed consent form for study participation

Exclusion Criteria:

• Co-infection with HCV or HIV; ② History of organ transplantation; ③ Presence of cardiac or renal insufficiency, or active autoimmune disease that constitutes a contraindication to immunotherapy.