Low-level viremia and the increased risk of hepatocellular carcinoma in patients receiving entecavir treatment.

The long-term clinical impact of low-level viremia (LLV; <2,000 IU/mL) is not well understood. As a result, it is unclear whether the development of LLV during entecavir monotherapy requires a change in therapy. A retrospective cohort of 875 treatment-naive chronic hepatitis B virus (HBV) monoinfected patients (mean age 47.7 years, male = 564 [65.5%], cirrhosis = 443 [50.6%]) who received entecavir monotherapy were analyzed for the development of hepatocellular carcinoma (HCC). The HCC risk was compared between patients who maintained virological response (MVR), defined by persistently undetectable HBV DNA (<12 IU/mL), and patients who experienced LLV, defined by either persistent or intermittent episodes of <2,000 IU/mL detectable HBV DNA. During a median 4.5 years of follow-up (range 1.0-8.7 years), HCC was diagnosed in 85 patients (9.7%). HCC developed more frequently in patients who experienced LLV than MVR (14.3% versus 7.5% at 5 years, P = 0.015). The hazard ratio comparing those with LLV to MVR was 1.98 (95% confidence interval = 1.28-3.06, P = 0.002, adjusted for age, sex, hepatitis B e antigen, baseline HBV DNA levels, and cirrhosis). Among patients with cirrhosis, those with LLV exhibited a significantly higher HCC risk than those with MVR (HCC incidence rate at 5 years 23.4% versus 10.3%, adjusted hazard ratio = 2.20, 95% confidence interval 1.34-3.60; P = 0.002). However, for patients without cirrhosis, there was no significant difference in the HCC risk between LLV and MVR. CONCLUSION: LLV observed during entecavir monotherapy was associated with a higher risk of HCC, especially for those with cirrhosis, indicating that LLV during potent antiviral therapy is consequential. (Hepatology 2017;66:335-343).