“Most patients with hepatitis B virus (HBV) infection do not know that they currently have or have had the infection,” explains Andrew S. Artz, MD, MS. “In patients whose immune systems are weakened—for example, due to immunosuppressive anticancer therapy—HBV can reactivate, start replicating, and lead to hepatitis flares, liver failure, and even death.” In response to awareness of patients with positive HBV test results who suffered serious liver outcomes during or after systemic anticancer therapy because they lacked an appropriate management plan, the American Society of Clinical Oncology (ASCO) updated its provisional clinical opinion (PCO) on HBV screening and management for patients with cancer before therapy, explains Jessica P. Hwang, MD, MPH.

Reviewing New Data

Along with colleagues on an expert panel, Drs. Artz and Hwang reviewed and analyzed studies on screening patients for HBV that had been published since the first PCO in 2015, also seeking to redefine recommendations to alleviate confusion regarding who should be tested. Published in Journal of Clinical Oncology, the PCO method was chosen over a guideline because of uncertainties in data concerning the phases of HBV management. “Although we currently lack robust studies, oncologists and patients need guidance about screening for and managing HBV infection,” says Dr. Artz. “We expect future versions of our HBV guidance could have sufficient data to evolve into a formal practice guideline if new, stronger data evolve around optimal management strategies especially for patients with a solid tumor or data-driven HBV reactivation risks attributed to specific anticancer therapies.”

Large, prospective, observational studies that focused on HBV screening, the prevalence of infection, predictive models of HBV infection, or HBV reactivation were reviewed. “One study showed that more than 20% of cancer patients with HBV had no identifiable HBV risk factors using a patient survey,” notes Dr. Hwang. “Another showed that approximately 90% of cancer patients who completed a longer CDC-based HBV risk survey would need serologic HBV testing, making the risk-based strategy impracticable.” Additional new data supported including hepatitis B surface antibody (anti-HBs) testing in the complete HBV assessment.

The Updated PCO

Important updates to the PCO suggest screening all patients with cancer for HBV before starting systemic anticancer therapy with three serologic tests: hepatitis B surface antigen (HBsAg), hepatitis B core antibody (anti-HBc; total or IgG), and anti-HBs. Patients who test positive for HBsAg or anti-HBc require evaluation and management while they proceed with anticancer therapy. The panel developed a process flow to screen and manage HBV for patients with cancer, demonstrated in the updated PCO, which was designed to serve as a reference guide for details on monitoring and management of patients with chronic or past HBV (Figure). Although the panel felt that the data on the timing and duration of antiviral therapy for solid tumor patients with HBV was weak, until stronger data become available, the PCO panel recommends antiviral prophylaxis for solid tumor patients with chronic HBV. For patients with a solid tumor and past HBV, the panel recommends monitoring.

“The updated PCO should simplify the clinical practice of HBV care for oncology providers,” says Dr. Artz. “Physicians should inform and request that their institutions and healthcare organizations implement systems-based approaches to order HBV tests and track test results through electronic medical records. Secondly, oncologists should collaborate with physicians experienced in caring for patients with HBV to provide personalized monitoring and HBV treatment plans.”

Future HBV Guidelines?

The panel looks to a time when data is strong enough to create a formal practice guideline. More specifically, Dr. Hwang believes further research is needed on the reactivation of HBV in patients with solid tumors. “Large, randomized studies are needed to determine optimal management strategies, such as antiviral prophylaxis or monitoring with initiation of antiviral prophylaxis at the first sign of HBV reactivation,” she says. Dr. Artz hopes that “as novel anticancer therapies emerge, we should be able to better predict HBV reactivation based on either the mechanism of action for the drug or specific host immune factors.”