Y 90 Ibritumomab Tiuxetan &Rituximab Relapsed or Refractory Diffuse Large B-Cell Non-Hodgkin's Lymphoma

RATIONALE: Monoclonal antibodies, such as yttrium Y 90 ibritumomab tiuxetan and rituximab, can locate cancer cells and either kill them or deliver radioactive cancer-killing substances to them without harming normal cells. Combining yttrium Y 90 ibritumomab tiuxetan with rituximab may kill more cancer cells. PURPOSE: Phase II trial to study the effectiveness of combining yttrium Y 90 Ibritumomab tiuxetan with rituximab in treating patients who have relapsed or refractory diffuse large B-cell non-Hodgkin's lymphoma.

OBJECTIVES: * Determine the best overall response in patients with relapsed or refractory diffuse large B-cell non-Hodgkin's lymphoma treated with yttrium Y 90 ibritumomab tiuxetan and rituximab. * Determine the event-free survival of patients treated with this regimen. * Determine the toxicity of this regimen in these patients. OUTLINE: This is an open-label, multicenter study. * Radioimmunotherapy: Patients receive indium In 111 ibritumomab tiuxetan IV over 10 minutes on day 1 (for imaging only); yttrium Y 90 ibritumomab tiuxetan IV over 10 minutes on day 8; and rituximab IV over 3-4 hours on days 1, 8, 15, 22, 29, and 36. * CNS ( central nervous system)prophylaxis: Patients receive CNS prophylaxis comprising intrathecal (IT) methotrexate or IT cytarabine on days 15, 22, 29, and 36 OR IT cytarabine (liposomal) on days 15 and 29. * Maintenance rituximab: Patients are assessed for response at week 14. Beginning at month 6, patients with stable or responding disease receive maintenance therapy comprising rituximab IV over 3-4 hours once weekly for 4 weeks. Maintenance therapy repeats every 6 months for 2 years (total of 4 courses) in the absence of disease progression or unacceptable toxicity. Patients are followed every 3 months for 2 years and then every 6 months for 2 years. PROJECTED ACCRUAL: A total of 40 patients will be accrued for this study within 2 years.