Screening and Prevention of Hepatitis B Virus Reactivation During Chemotherapy.

Hepatitis B virus (HBV) infection is common across the world. Infection can lead to significant morbidity from cirrhosis and hepatocellular carcinoma. An estimated 240 million people have chronic (hepatitis B surface antigen [HBsAg]-positive) HBV infection.[1] As a result of increasing immigration from highly endemic areas (eg, China, Southeast Asia, Africa, Eastern Europe), the prevalence of chronic infection in the United States is rising and is estimated to be 1.5 million.[2] Across the country, the overall age-adjusted prevalence of chronic infection and evidence of exposure to infection (defined by the presence of antibody to HBV core antigen [anti-HBc] in the absence of HBsAg) have been reported to be 0.3% and 4.7%, respectively[3]; however, rates are much higher and can approach 10% to 15% in certain cities. In addition, many patients with HBV infection are unaware that they are infected.[4,5] At the same time, it is estimated that over 40% of the US population will develop some type of cancer during their lifetime,[6] and most patients will receive immunosuppressive therapy (IST) as treatment for their malignancy. This is notable because patients with chronic HBV infection or evidence of prior HBV infection who are exposed to IST are at risk for HBV reactivation.[7,8] We will discuss HBV reactivation in order to raise awareness of the problem and to detail our strategy for preventing this potentially severe complication of IST.