# Hepatitis B testing before cancer treatment and prevention of reactivation

Source: https://onco.cc/protocols/hepatitis-b-screening-and-reactivation-prophylaxis/  
OnCo record `hepatitis-b-screening-and-reactivation-prophylaxis` (Protocol). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Hepatitis B can sleep in the liver for years and wake up when cancer treatment weakens the immune system, sometimes damaging the liver badly. A blood test before treatment finds people at risk. Those who have it, or have had it and get high-risk treatment such as rituximab or a stem cell transplant, take an antiviral tablet during and for at least a year after treatment, or are checked closely.

## Summary

ASCO's 2020 Provisional Clinical Opinion moved from risk-based to universal testing: everyone anticipating systemic anticancer therapy has HBsAg, anti-HBc (total Ig or IgG) and anti-HBs before or at the start of treatment, without delaying it (strong). Chronic HBV (HBsAg-positive) on any systemic anticancer therapy gets antiviral prophylaxis for the whole of treatment and at least 12 months after, with ALT and HBV DNA at baseline and every 6 months, monthly ALT for 3 months after stopping antivirals, and a clinician experienced in HBV (strong). Past HBV (HBsAg-negative, anti-HBc-positive) with anti-CD20 antibodies or stem cell transplant gets prophylaxis from the start and for at least 12 months after (strong), or, where follow-up can be relied on, HBsAg and HBV DNA every 3 months with antivirals at the first sign of reactivation (HBsAg appears or HBV DNA above 1,000 IU/mL). Past HBV with other regimens is monitored with HBsAg and ALT every 3 months. Hormonal therapy alone follows non-cancer HBV guidance (moderate).

APASL 2021 stratifies by the risk of the immunosuppressive therapy and by liver fibrosis, prefers entecavir, tenofovir or TAF (evidence I, recommendation 1), and considers stopping nucleos(t)ide analogues 6 months after immunosuppression ends in selected patients, where ASCO says at least 12 months. Anti-HBc can be falsely positive after intravenous immunoglobulin, so testing before IVIG is simpler to read.

## Fields

- Kind: Protocol
- Last checked: 2026-11-11
- Also known as: HBV screening before chemotherapy; hepatitis B reactivation prophylaxis; HBV reactivation; anti-HBc positive before rituximab; entecavir prophylaxis
- Tags: protocol; hepatitis-b; infection-prevention

## Connected records

- terms: [Hepatitis B and C as cancer causes](https://onco.cc/terms/hbv-hcv/), [Hepatitis B reactivation before rituximab and other anti-CD20 antibodies](https://onco.cc/terms/lymphoma-tx-hepatitis-b-reactivation/)
- cancers: [Chronic lymphocytic leukaemia](https://onco.cc/cancers/cll/), [Diffuse large B-cell lymphoma](https://onco.cc/cancers/dlbcl/), [Non-Hodgkin lymphoma (all types)](https://onco.cc/cancers/non-hodgkin-lymphoma/)
- fronts: [Supportive Care & Survivorship](https://onco.cc/fronts/supportive-care/)
- technologies: [Allogeneic stem cell transplantation](https://onco.cc/technologies/allogeneic-hsct/), [Autologous stem cell transplant (high-dose therapy)](https://onco.cc/technologies/autologous-stem-cell-transplant/)
- drugs: [Obinutuzumab](https://onco.cc/drugs/obinutuzumab/), [Rituximab](https://onco.cc/drugs/rituximab/)
- institutions: [American Society of Clinical Oncology (ASCO)](https://onco.cc/institutions/asco/)
- ideas: [Hepatitis B blood tests before anyone starts systemic cancer treatment, with antiviral tablets for those who need them](https://onco.cc/ideas/idea-upgrade-hepatitis-b-testing-before-systemic-treatment/)

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