Clinical algorithm for universal screening for hepatitis B virus (HBV) and management in patients initiating systemic anticancer therapy

HBsAg: hepatitis B surface antigen; HBc: hepatitis B core antibody; Ig: immunoglobulin; IgG: immunoglobulin G; HBV: hepatitis B virus; ALT: alanine aminotransferase; IU: international units.
* Evidence of HBV infection refers to HBsAg–positive or HBc–positive (either total Ig or IgG; do not order IgM unless acute HBV infection is suspected). If evidence of HBV infection, do not delay anticancer therapy while obtaining further testing or referrals.
¶ Past HBV: HBsAg-negative, anti-HBc–positive, regardless of anti-HBs status. A positive anti-HBs test likely attenuates the risk of reactivation in patients with past HBV infection.
Δ All other systemic anticancer therapy besides anti-CD20 therapy or stem-cell transplantation. Due to the lack of strong data, the risk of HBV reactivation is unclear for specific anticancer drugs besides anti-CD20 therapy or stem-cell transplantation. It is possible that these anticancer therapies have a low risk of reactivation for patients with past HBV infection and may not require routine monitoring.
◊ An alternative pathway is careful monitoring with HBsAg and HBV DNA every three months with immediate antiviral therapy at the earliest sign of HBV reactivation so long as patients and providers are able to adhere to frequent and consistent follow-up during and for up to 12 months after last anticancer therapy.
§ Hepatitis flare: ALT. 100 U/mL and 3 times baseline.^[1]
¥ Long-term antiviral therapy management for patients with cancer after the cessation of anticancer therapy should follow national hepatology recommendations for all patients with chronic HBV.^[1,2] An HBV specialist is a clinician experienced in HBV management.