Rituximab and Yttrium Y 90 Ibritumomab Tiuxetan in Treating Patients With Non-Hodgkin's Lymphoma

RATIONALE: Monoclonal antibodies, such as rituximab, can block cancer growth in different ways. Some block the ability of cancer cells to grow and spread. Others, such as yttrium Y 90 ibritumomab tiuxetan, find cancer cells and help kill them or carry cancer-killing substances to them without harming normal cells. Giving rituximab together with yttrium Y 90 ibritumomab tiuxetan may kill more cancer cells. PURPOSE: This phase II trial is studying how well giving rituximab together with yttrium Y 90 ibritumomab tiuxetan works in treating patients with indolent non-Hodgkin's lymphoma.

OBJECTIVES: Primary * Determine 12-week overall and complete response rate in patients with indolent non-Hodgkin's lymphoma treated with rituximab and yttrium Y 90 ibritumomab tiuxetan as first-line treatment. Secondary * Determine 1-year event-free survival of patients treated with this regimen. * Determine time to progression and time to next antilymphoma therapy in patients treated with this regimen. * Determine the molecular response rate in patients treated with this regimen. * Determine the hematological and non-hematological toxicity of this regimen in these patients. * Assess the quality of life of patients treated with this regimen. OUTLINE: This is an open-label, multicenter study. Patients receive rituximab IV followed, no more than 4 hours later, by indium In 111 ibritumomab tiuxetan (for imaging) IV over 10 minutes on day 1. If biodistribution is acceptable, patients receive rituximab IV followed, no more than 4 hours later, by a single dose of yttrium Y 90 ibritumomab tiuxetan IV over 10 minutes on day 7, 8, or 9 in the absence of disease progression or unacceptable toxicity. Quality of life is assessed at baseline, weeks 6, 10, and 14, every 3 months for 2 years, and then every 6 months for 2 years. After completion of study treatment, patients are followed weekly for 3 months, every 3 months for 2 years, and then every 6 months for 2 years. PROJECTED ACCRUAL: A total of 18-28 patients will be accrued for this study within 2 years.