Trends in hepatitis B virus seroprevalence in a large cohort of adult cancer patients from 2010 to 2023

Abstract Purpose Hepatitis B virus (HBV) infection poses increased risks for cancer patients due to immunosuppression and potential viral reactivation. We evaluated the seroprevalence and temporal trends of HBV exposure in a large cohort of cancer patients in Brazil. Methods Adult patients who underwent anti-HBc testing at a quaternary oncology center between 2010 and 2023 were included in this retrospective study, and HBV exposure was defined as anti-HBc positivity. Temporal trends were assessed by using linear regression, whereas associated factors were evaluated by using multivariable logistic regression. Results Anti-HBc testing was performed in 22.9% (28,869/125,985) of admitted cancer patients, and seroprevalence was 13.4% (3,857/28,869), declining from 16.5 in 2010 to 9.9% in 2023 ( p < 0.001). Decreasing trends were observed across sexes and age groups ( p < 0.001 for both), with a more pronounced decline among men (25.1%–12.3%). Seroprevalence also decreased significantly among White patients (16.7%–7.9%; p < 0.001) and those with solid tumors (18.8%–9.0%; p < 0.001), but not among non-White individuals (21.4%–17.7%; p = 0.246) or those with hematological malignancies (13.1%–12.8%; p = 0.136). Age ≥ 60 years (OR = 4.40; 95%CI: 3.77–5.12; p < 0.001), men (OR = 1.89; 95%CI: 1.76–2.04; p < 0.001), and non-White ethnicity/color (OR = 1.25; 95%CI: 1.15–1.35; p < 0.001) were independently associated with HBV exposure. Conclusion Despite the declining seroprevalence over time, HBV exposure remains common among cancer patients, as persistent disparities across demographic groups underscore the need for expanded vaccination and systematic screening.