Although hepatitis B virus (HBV) reactivation is a potentially fatal complication of chemotherapy, “provided that HBV carriers are recognized, HBV reactivation can be largely prevented through the administration of oral antinucleoside analogs,” researchers at the University of Toronto noted in an article in the Journal of Oncology Practice. However, a survey they conducted among practicing hematologists/oncologists in Canada revealed that many respondents often underestimated the risk of HBV reactivation, and their “knowledge regarding risk factors for HBV carriage seems to be low, potentially undermining the success of a selective screening strategy,” the researchers reported.
“Current guidelines recommend HBV screening before chemotherapy, although there are some discrepancies among published recommendations,” the investigators wrote. “Infectious disease and hepatology bodies recommend universal screening, whereas the lead oncology society recommends consideration of targeted testing of high-risk individuals. Targeted testing is predicated on the assumption that physicians are aware of the risks of HBV reactivation and able to identify those at highest risk of HBV carriage.” The survey results showed, however, that only 33% identified the major risk factor for HBV—birth in an endemic area—and only 2% correctly identified all continents having HBV endemic regions.
The authors estimated that approximately 0.3% to 0.5% of the population in the United States and 2% of the population in Canada are affected by HBV. “Reactivation hepatitis is associated with substantial morbidity and mortality,” they reported. “Estimates of the risk of reactivation in asymptomatic HBV carriers range from 20% to more than 70% depending on tumor type and chemotherapy administered. Risk factors for HBV reactivation include high HBV viral load before treatment, HBeAg positivity, young age, treatment of hematologic malignancies, use of glucocorticoids, use of rituximab [Rituxan], and bone marrow/hemapoeitic stem-cell transplantation.”
Contributors to Low Screening Levels
Physicians responding to the survey “tended to underestimate the risk of HBV reactivation in both solid and hematologic tumors. For instance, most respondents estimated the risk of HBV reactivation in patients receiving chemotherapy for a hematologic malignancy as being less than 30%, whereas the literature suggests that the actual risk is greater than 50% in this population,” the researchers noted.
“Slightly more than half of respondents (58%) reported screening for HBV before chemotherapy (36% employed selective screening; 22% employed universal screening). Forty percent of respondents never or rarely screened their patients,” the authors wrote. “The most commonly cited reasons for not testing were a perception that HBV incidence was low in the respondent’s practice, and a perceived absence of guidelines or evidence recommending HBV testing. Only 27% of respondents indicated that they were aware of existing guidelines regarding HBV screening before chemotherapy,” the researchers stated.
“A similar study was conducted in the United States involving oncologists registered with the American Medical Association,” the researchers reported. “Although limited by a low response rate (5%), it showed similar findings: 20% of respondents reported never screening patients for HBV before chemotherapy, 38% reported only screening in the presence of abnormal liver biochemistry results, and 30% reported screening in the presence of risk factors or a known history of hepatitis. ■