At the end of the remission induction phase, participants will undergo tests to determine if they are in remission. This testing will involve getting samples of blood, bone marrow and spinal fluid to look for cancer cells under the microscope. This testing will also involve getting repeat scans if these were not normal at the time of diagnosis. Remission means that cancer cells cannot be detected under the microscope in the blood, marrow and spinal fluid, and that any cancer previously seen on a scan has significantly improved or is no longer seen. Participants must be in remission to go onto the next phases of treatment; alternative treatments will be discussed with participants who are not in remission at the end of the induction phase.