Role of hepatitis B surface antigen in hepatitis B virus relapse after entecavir or tenofovir prophylaxis in patients undergoing cancer chemotherapy

Background and Aim This study investigated whether hepatitis B surface antigen (HBsAg) could predict hepatitis B virus (HBV) relapse after cessation of entecavir or tenofovir disoproxil fumarate (TDF) prophylaxis for chronic hepatitis B cancer patients who are undergoing chemotherapy. Methods The study enrolled 122 hepatitis B e‐antigen‐negative cancer patients who underwent chemotherapy with entecavir or TDF for antiviral prophylaxis and posttreatment follow‐up for at least 6 months. Results Of the 122 patients, 52 and 18 experienced virological and clinical relapse, which had 3‐year cumulative incidences of 46.6% and 18.6%, respectively. Multivariate analysis showed that end‐of‐treatment HBsAg levels and baseline HBV‐DNA ≥ 2000 IU/mL were independent predictors of virological relapse. The best HBsAg cutoff value was 500 IU/mL. An end‐of‐treatment HBsAg of 500 IU/mL was useful for predicting virological relapse in patients with baseline HBV‐DNA