Hepatitis B reactivation after oral capecitabine treatment in a rectum cancer patient with isolated anti-HBc IgG positivity

Introduction Hepatitis B virus (HBV) reactivation in the setting of chemotherapy and immunosuppressive therapy is associated with significant morbidity and mortality. Herein we present a case of HBV reactivation after oral capecitabine treatment in a patient with rectum cancer and isolated anti-HBc IgG positivity. Case report A 57-year-old man was consulted from the oncology clinic because of increased serum liver tests after chemotherapy. He underwent surgery for early-stage rectal cancer and received adjuvant chemotherapy with oral capecitabine. After cessation of chemotherapy, his laboratory tests revealed severe liver dysfunction. HBV markers showed positivity for hepatitis B surface antigen (HBsAg) and hepatitis B core antibody (anti-HBc). HBV DNA level was markedly elevated. Management and outcome A review of medical records revealed that, before chemotherapy, the patient was positive for anti-HBc IgG but negative for HBsAg, and serum aminotransferases were within the normal limits. A diagnosis of HBV-related hepatitis due to capecitabine use was made, and the patient was put on tenofovir treatment. Six months later, HBV DNA decreased, and liver function tests were normalized. Discussion To the best of our knowledge, this is the first case report describing HBV reactivation after chemotherapy with capecitabine for rectal cancer in a patient with isolated anti-HBc IgG positivity. Our case shows that HBV reactivation may develop in a low-risk patient with a low degree of immunosuppression.