Rituximab, Fludarabine, Mitoxantrone, Dexamethasone (R-FND) Plus Zevalin for High-Risk Follicular Lymphoma

The goal of this clinical research study is to learn if chemotherapy given with rituximab, followed by Ibritumomab tiuxetan (Zevalin), and then followed by rituximab can help to control lymphoma. The safety of this treatment schedule will also be studied. Objectives: 1. To assess whether the time to progression for these high-risk patients can be prolonged to a median of 36 months, compared to the historical expectation of approximately 24 months. 2. To assess the tolerance and efficacy of Y2B8 (Zevalin) after R-FND (rituximab, fludarabine, mitoxantrone, dexamethasone) in patients with high-risk stage III-IV follicular lymphoma 3. To assess overall response, failure-free survival, and survival of this strategy compared to our historical experience with FND (fludarabine, mitoxantrone, dexamethasone) alone or R-FND 4. To assess the tolerance and efficacy of maintenance therapy with rituximab. 5. To maximize the 12-month molecular remission rate for patients with high-risk stage III-IV follicular lymphoma 6. to correlate the results of quantitative PCR assay with classical PCR and with clinical outcome