Prevalence and serological profile of occult hepatitis B virus infection in newly diagnosed cancer patients

Occult hepatitis B virus infection (OBI) represents a diagnostic and clinical challenge, particularly among cancer patients who are at risk of viral reactivation during immunosuppressive therapy. Limited data are available from India on the prevalence and characteristics of OBI in malignancy. This study aimed to determine the prevalence and describe the serological profile of OBI among newly diagnosed cancer patients at a tertiary care hospital.

A cross-sectional study was conducted in 2023, including 100 newly diagnosed cancer patients prior to chemotherapy or radiotherapy. Serum samples negative for Hepatitis B surface antigen (HBsAg) were screened for HBV DNA using quantitative real-time PCR. Serological testing for IgM anti-HBc, Total anti-HBc and anti-HBs antibodies was performed on OBI-positive cases. Demographic and clinical variables were analyzed descriptively.

OBI was detected in 7% (7/100) of patients, with HBV DNA levels ranging from 79 to 64,533 IU/mL (mean: 10,823 IU/mL; median: 519 IU/mL). Among OBI-positive individuals, 42.8% were seropositive (anti-HBc and/or anti-HBs positive) and 57.1% were seronegative.

A 7% prevalence of OBI was observed among treatment-naïve cancer patients, with notably high HBV DNA levels compared to existing data. The presence of OBI in both vaccinated and seronegative individuals highlights the inadequacy of serology-based screening. Incorporating HBV DNA testing into routine pre-chemotherapy and radiation therapy screening is strongly recommended to prevent reactivation and improve safety in cancer management.