A Study to Investigate Whether the Immediate Use or Deferred Use of an Anti-viral Drug Lamivudine Will Help to Better Safe-guard the Delivery of Chemotherapy in Patients With Cancer Who Are Also Hepatitis B Carriers

Inclusion Criteria: 1. Patient with histology-proven malignant solid tumor other than malignant lymphoma 2. Patients with age between 18 and 75 3. Patients with Karnofsky performance score (KPS) of at least 60 4. Patients planned for at least 4 cycles of intensive cytotoxic chemotherapy (either as part of curative therapy or as palliative therapy), except for those receiving single agent cisplatin chemotherapy alone concurrently with radiation for radiosensitization 5. Patients with at least 6 months' life expectany from date of recruitment 6. Patients with normal liver function tests including alanine aminpotransferase (ALT), alkaline phosphatase (ALP), gamma glutamyl-transpeptidase (GGT), and bilirubin 7. Patients with no known history of radiological \&/or histological diagnosis of chronic active hepatitis or cirrhosis of any cuase, or history of prior hepatitis B reactivation, or prior chronic therapy for HBV within 6 months 8. Patients with no evidence of autoimmune hepatitis, hepatitis C or delta virus infection, HIV infection or radiological evidence of liver metastasis 9. Patients with negative pregnancy test for female gender of child-bearing age Exclusion Criteria: 1. Patients with age \< 18 and \> 75 2. Patients with Karnofsky performance score (KPS) of \< 60 3. Patients planned for single agent cisplatin chemotherapy alone concurrently with radiation for radiosensitization 4. Patients with \< 6 months' life expectancy from date of recruitment 5. Patients with abnormal liver function tests including alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma glutamyl- transpeptidase (GGT), and bilirubin 6. Patients with known history or radiological and/or histological diagnosis of chronic active hepatitis or cirrhosis of any cause, or history of prior hepatitis B reactivation, or prior chronic therapy for HBV within 6 months 7. Patients with autoimmune hepatitis, hepatitis C or delta virus infection, HIV infection or radiological evidence of liver metastasis 8. pregnant female patients