 Since results of our previous study has indicated that nearly all clinical hepatitis developed in HBV carrier during chemotherapy is caused by HBV reactivation, and serum HBV DNA data are not readily available in most hospitals, all patients with hepatitis flare-up are considered HBV reactivation until proved otherwise. For patients in the second arm, biochemical hepatitis will prompt a start of daily lamivudine, even before a definite documentation of 10-fold increase of HBV DNA. For patients with only minor hepatic dysfunction total bilirubin 3.0 mgdl and ALT 200 I.U.L, full-dose chemotherapy is recommended on the scheduled treatment day without delay. For patients with more severe hepatic dysfunction total bilirubin 3.0 mgdl or ALT 200 I.U.L, subsequent course is postponed for 1 week and the dosage modified as followings if the values remain abnormal after 1 week: 