Hepatitis B Virus (HBV) Screening

This course will provide a brief overview of the causes of HBV reactivation, the importance of HBV screening prior to chemotherapy, the current methods of HBV screening, and ways in which we can improve the HBV screening rate at our institution.

HBV Reactivation

HBV Background

  • HBV is a viral infection
    • Attacks the liver
    • Can cause both acute and chronic forms of disease
    • Transmitted through blood or bodily fluids
  • HBV affects approximately 2% of the Canadian population

What is HBV Reactivation?

  • HBV reactivation:
    • Loss of immune control over HBV in patient with an inactive or resolved HBV infection

    • Usually presents as HBV DNA rise – reappearance of > 1 log increase

      • Reverse seroconversion = reappearance of HBsAg in HBsAg –ve person, anti-HBc +ve

Clinical Manifestations of HBV Reactivation

  • Range of symptoms from subclinical to severe/fatal hepatitis
  • Rise in HBV DNA +/- return of HBeAg

  • ALT increase (may be mild or very dramatic)

  • May progress to liver failure/death despite antiviral treatment

Risk Factors of Reactivation

  1. Malignancy
    • 40-58% of HBsAg +ve patients with Non Hodgkin's Lymphoma may experience reactivation

    • 20-41% of HBsAg +ve patients with Breast cancer may experience reactivation

  2.  Chemotherapy

    • Prednisone, anthracyclines, rituximab use leads to increased risk

    • Immunosuppression

  3.  HBV DNA

    • If detectable, increased risk

    • Risk is elevated if HBeAg +ve

  4. Demographics

    • Men>women

 

**HBeAg+ = Active viral replication, HBeAg- = No active replication

Agents that may cause Reactivation

Which of the following are associated with an increased risk of HBV reactivation?

  • Immunosuppression therapy
  • Anti-CD20 monoclonal antibody treatment
  • Reappearance of HBV DNA
  • All of the above

What are the clinical manifestations of HBV reactivation?

  • Rise in HBV DNA
  • ALT increase
  • Rise in HBC DNA
  • A and B

HBV Screening

Who should be screened?

Information Provided From HBV Screening Tests

Standardized HBV lab ordering set

Why is HBV Screening Important?

  • Pre-emptive antiviral therapy can reduce the instances of HBV reactivation
    • Pre-emptive therapy requires pre-emptive screening!
  • National Institute for Health Care Excellence HBV guideline:
    • ALL immunocompromised individuals found to be HBsAg positive should beign antiviral therapy prior to chemotherapy, and continue for 6 months post chemotherapy
    • http://www.bmj.com/content/346/bmj.f3893

Who should be screened for HBV prior to chemotherapy?

  • All patients
  • Male patients only
  • Only patients with a previous HBV infection
  • Only patients treated with rituximab

What test should you screen for patients receiving standard chemotherapy?

  • Screen HBsAg
  • Screen anti-HBc
  • Screen anti-HBs
  • Screen all of the above

Pre-emptive Anti-viral Therapy

Which agent to choose?

Timeline

  • When to start antiviral therapy?
    • Ideally before/with chemotherapy

    • Do not delay start of chemotherapy

  • When to stop antiviral therapy?

    • Baseline HBV DNA>2000 IU/mL – high risk of withdrawal flare

    • Continue therapy as per chronic HBV

    • Baseline HBV DNA<2000 IU/mL – 6-12 mo after end of chemotherapy

    • Monitor for withdrawal flares (monthly HBV DNA/ALT)

Which statement is correct in regards to pre-emptive antiviral therapy?

  • It is ideal to start after chemotherapy
  • If needed, one could delay the start of chemotherapy to wait for pre-emptive antiviral treatment
  • If a patient’s HBV DNA is >2000 IU/mL, Entecavir/Tenofovir are a good option for pre-emptive treatment
  • If a patient’s Baseline HBV DNA is >2000 IU/mL there is a low risk of withdrawal flare

How Can We Improve the HBV Screening Rate?

Methods to Improve

  • Universal HBV screening rates in the oncology community are less than 20%
  • St. Michael’s interventions implemented to increase HBV screening rate:
    • HBV screening posters in assessment and treatment areas of oncology clinic
    • HBV screening educational sessions for all team members
    • Pharmacist’s chemotherapy assessment tool updated to include HBV screening