A case of the usage of entecavir to prevent hepatitis B virus reactivation during chemotherapy in breast cancer patient

Hepatitis B virus (HBV) reactivation is a serious clinical problem for HBV infected patients, and one of its possible causes is chemotherapy for malignant disease. At the onset of active hepatitis, planned chemotherapy should be discontinued and acute or fetal fulminant hepatitis must be induced in some cases. Therefore, it is desirable to prevent virus reactivation during chemotherapy in HBV-positive patients. We report a case in which adjuvant chemotherapy for a breast cancer patient was accomplished safely by using entecavir. The patient was a 48-year-old woman with breast cancer whose HBV infection had been pointed out when she was 20 years old. Breast reconstruction was performed, followed by mastectomy. Pathological findings were invasive ductal carcinoma, three positive nodes, estrogen and progesterone receptor-positive, and HER2-negative. An adjuvant chemotherapy with anthracycline followed by taxane was planned. Blood chemistry revealed the seroconversion of HBV and the quantity of HBV-DNA was 2. 8 log copies/mL. Administration of the anti-virus agent, entecavir, was started three weeks before chemotherapy. The HBV-DNA was decreased under the titer of detection and no re-increase in HBV-DNA was found during chemotherapy. Planned chemotherapy was accomplished safely without HBV reactivation.