<qa>  What is a randomized, multicenter study?OUTLINE: This is a randomized, multicenter study. Patients are stratified according to relapse relapsed more than 6 months after either initial complete remission CR or CR with positive positron emission tomography or MRI gallium vs failed to achieve initial CR or relapsed within 6 months after either initial CR or CR with positive PET or MRI gallium and prior rituximab yes vs no. 