Study design and patients
We performed a retrospective cohort study on unresectable HCC patients who were seropositive for HBsAg and accepted TAF therapy prior to combined anti-PD-1 and antiangiogenic treatment. This study included consecutive patients who were referred to Nanfang Hospital, Southern Medical University in Guangzhou, China, between Jul 2019 and Oct 2021. A total of 108 patients were screened for eligibility according to the following inclusion criteria: (1) pathologically diagnosed with HCC; (2) received at least one cycle of anti-PD-1 therapy; (3) seropositive for HBsAg and had received TAF therapy as a regular antiviral regimen before anti-PD-1 treatment; and (4) with HBV DNA and liver function monitored regularly during the follow-up. Patients were excluded for: (1) the presence of other positive viral markers, including IgM antibodies to the hepatitis A virus, hepatitis C virus (HCV), or hepatitis E virus, IgG antibodies to the hepatitis D virus or HIV; (2) participating in other clinical trials; and (3) not having baseline HBV DNA and HBsAg test results (baseline defined as within 2 weeks prior to initial PD-1 inhibitor therapy). Finally, 70 patients with complete data were included in the current study. Figure 1 shows a flowchart of the patient selection procedure. This study was performed in accordance with the ethical guidelines of the 1975 Declaration of Helsinki and was approved by the ethics committee of the Nanfang Hospital, Southern Medical University. Informed consent was obtained from all the patients prior to their participation.