Use of lamivudine to prevent hepatitis B virus reactivation during chemotherapy in breast cancer patients

In parts of Asia, about 10% of the population have chronic hepatitis B virus (HBV) infection, and cancer patients who are HBV carriers are frequently complicated by HBV reactivation while receiving cytotoxic chemotherapy. The condition may result in varying degrees of liver damage, causing disruption in chemotherapy and compromising the patients' prognosis. With the increasing use of chemotherapy paralleling the rise in breast cancer incidence, the occurrence of HBV reactivation is likely to further increase. Recent reports have suggested that the anti-viral agent, lamivudine, may reduce HBV reactivation and its associated morbidity. However, most studies are based on small series of lymphoma patients, while information on the other high risk population, namely breast cancer patients, has been lacking. In this study, we studied the role of lamivudine in preventing HBV reactivation and its associated morbidity in breast cancer patients with chronic HBV infection who were planned for chemotherapy. Two groups were studied. One group consisted of 31 patients who received 'prophylactic lamivudine' prior to and until 8 weeks after discontinuing chemotherapy. The other comprised of 61 historical controls who underwent chemotherapy without prophylactic lamivudine. The outcomes, in terms of the efficacy of lamivudine in reducing the incidence of HBV reactivation, and diminishing morbidity during chemotherapy were compared. The results revealed that in the prophylactic lamivudine group, despite a significantly higher proportion receiving anthracyclines, there was significantly fewer incidences of hepatitis (12.9 vs. 59.0%, p < 0.001), less HBV reactivation (6.5. vs. 31.1%, p=0.008), and less disruption of chemotherapy (16.1% vs. 45.9%, p=0.006). We conclude that prophylactic lamivudine significantly reduces the incidence of HBV reactivation and the overall morbidity of breast cancer patients undergoing chemotherapy.