Patients with non-lymphoma and non-leukaemia cancer who are also hepatitis B carriers will have a risk of hepatitis B reactivation during chemotherapy. Lamivudine can be used effectively to control hepatitis upon reactivation during chemotherapy and the chemotherapy may not need to be interrupted. The study aims to investigate whether adding the anti-viral drug Lamivudine at the start of chemotherapy for all patients, rather than at the time of hepatitis reactivation for those with reactivation, will help to improve the delivery of chemotherapy in these patients.