Division of Gastroenterology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC.
Hepatitis B virus (HBV) reactivation induced by cytotoxic chemotherapy is an important issue in cancer patients. An elevated HBV viral load usually precedes hepatitis flare, and hepatic decompensation and eventual death is not infrequent once viral reactivation is initiated. Reverse seroconversion from hepatitis B surface antigen (HBsAg)-negative to HBsAg-positive would also occur in hepatitis B core antibody (anti-HBc)-positive patients. The risk of HBV reactivation can be attributed to patient viral status and the regimen of chemotherapeutic agents. Chemotherapeutic regimens that contain steroid and rituximab can increase the risk of viral reactivation in lymphoma patients. Consequently, routine HBV marker screening, including HBsAg and anti-HBc, is mandatory prior to chemotherapy for all cancer patients, and prophylactic antiviral treatment is highly recommended for HBsAg-positive cases. However, for patients who are anti-HBc-positive and HBsAg-negative, so-called resolved hepatitis B patients, regular HBV viral load survey during the course of chemotherapy is necessary to early detect HBV reactivation. Currently, the role of antiviral prophylaxis for resolved hepatitis B patients is still unsettled.