Prevalence and risk factors of hepatitis B virus reactivation in patients with solid tumors with resolved HBV infection

Background Reports of hepatitis B virus (HBV) reactivation in solid tumors are very limited, and their frequencies and risk factors were previously unknown. Aim To evaluate the prevalence and risk factors of HBV reactivation in patients with solid tumors with resolved HBV infection. Methods All 1088 patients with solid tumors were assessed for eligibility; 251 patients had resolved HBV infection (negative for HBs antigen and positive for anti‐HBc antibody and/or positive for anti‐HBs antibody), and HBV‐DNA was assessed for 243 of these patients in whom we analyzed the prevalence of HBV reactivation. Risk factors for HBV reactivation were exploratorily evaluated by analysis of a case–control study. Results The prevalence of HBV‐DNA reactivation was 2.1% (95% confidence interval [CI], 0.3–3.9%). We did not observe any exacerbation of HBV‐DNA by early intervention. A low anti‐HBs antibody titer (1.0 mg/day) were high risk factors, with odds ratios of 5.94 (95% CI, 1.15–30.6, P = 0.03) and 8.69 (95% CI, 1.27–58.8, P = 0.02), respectively. Conclusion HBV reactivation in solid tumor patients was relatively rare. Therefore, risk factors that can identify targets for HBV screening must be determined in future studies.