Relationship between HBsAg, HBcrAg and hepatocellular carcinoma in patients with undetectable HBV DNA under nucleos(t)ide therapy.

We examined the relationship between hepatitis B surface and core-related antigens (HBsAg, HBcrAg) and hepatocellular carcinoma (HCC) development in patients with undetectable serum HBV DNA receiving nucleos(t)ide analogue (NA). Seventy-six HBV carriers with undetectable HBV DNA (<20 IU/mL) who subsequently developed HCC were compared with 152 matched controls. Clinical and laboratory parameters (including novel assays to measure linearized HBsAg [HQ-HBsAg] and HBcrAg) were analysed. There were no significant differences in HBsAg/HQ-HBsAg levels between the two groups. There was a significant difference in the median values of both pre- and post-NA HBcrAg levels between the HCC and control groups (pre-treatment: 279.0 vs 35.4 kU/mL, P=.005; post-treatment: 10.2 vs 1.7 kU/mL, P=.005, respectively). For the whole HCC group, a cut-off value of post-treatment HBcrAg level ≥7.8 kU/mL yielded an area under receiver operating curve (AUROC) of 0.61 with a negative predictive value (NPV) of 77.0%. The OR of HCC development was 3.27. For noncirrhotic patients, the median values of post-treatment HBcrAg level of HCC group and controls were 10.2 and 1.0 kU/mL, respectively (P=.001). A cut-off value of HBcrAg level ≥7.9 kU/mL yielded an AUROC of 0.70 with a NPV of 80.6%. The OR of HCC development was 5.95. A higher pre- and post-NA treatment HBcrAg level (but not HBsAg) was associated with an increased risk of HCC development in patients achieving undetectable serum HBV DNA while on NA therapy. HBcrAg may serve as a novel risk marker for HCC in this group of patients.