Yttrium Y 90 Ibritumomab Tiuxetan, Etoposide, Cyclophosphamide, and an AHSCT in Non-Hodgkin's Lymphoma Patients

DISEASE CHARACTERISTICS: * Biopsy proven diagnosis of low- or intermediate-grade\* non-Hodgkin lymphoma (NHL) including any of the following: * Follicular small cleaved * Follicular mixed * Follicular large cell * Diffuse small cleaved * Diffuse mixed * Diffuse large cell * Immunoblastic (working formulation B, C, D, E, F, G and H) NOTE: \*A new classification scheme for adult non-Hodgkin lymphoma has been adopted by PDQ. The terminology of "indolent" or "aggressive" lymphoma will replace the former terminology of "low-", "intermediate-", or "high-" grade lymphoma. However, this protocol uses the former terminology. * Mantle cell and transformed low-grade lymphomas allowed * Demonstrated monoclonal CD20-positive B-cell population in lymph nodes and/or bone marrow * Favorable biodistribution on imaging dose * Patient either relapsed after achieving a complete (CR) or partial response (PR) to prior therapy, never responded to prior therapy, or has poor-risk disease * Sensitivity of disease based on 1 of the following: * Induction failure: patients who did not achieve a CR or PR from induction chemotherapy * Resistant relapse: patients who did not achieve a CR or PR from the most recent standard salvage chemotherapy * Sensitive relapse: patients who did achieve a CR or PR from the most recent standard salvage chemotherapy * Poor-risk disease defined as any of the following: * Age-adjusted International Prognostic Index (IPI) High- (3 risk factors) or High-Intermediate (2 risk factors) based on the following risk factors: * Stage III-IV disease * Elevated serum lactate dehydrogenase level * ECOG performance status 2-4 * Patients with aggressive NHL including mantle cell lymphoma and who required 2 different induction chemotherapy regimens to achieve a CR/PR * Patients with B-cell NHL and who failed to achieve a CR after adequate induction chemotherapy regimen(s) * Patients must have bone marrow aspiration and biopsy within 42 days before salvage chemotherapy or stem cell collection which show ≤ 10% lymphomatous involvement of total cellularity * Normal cytogenetic study on bone marrow (prior to salvage chemotherapy or stem cell collection) * Cytogenetic study on peripheral blood is acceptable if bone marrow biopsy has already been done and shows no sign of myelodysplastic syndrome (MDS) or lymphoma and a repeat bone marrow is deemed unnecessary by attending physician * No active or prior history of CNS diseases * No human anti-mouse antibody (HAMA) or human anti-chimeric antibody PATIENT CHARACTERISTICS: * ECOG performance status (PS) 0-1 or Karnofsky PS 80-100% * Platelet count normal * Serum creatinine ≤ 1.5 mg/dL or creatinine clearance ≥ 60 mL/min * FEV\_1 \> 65% of predicted or DLCO ≥ 50% of predicted * LVEF \> 50% by ECHO or MUGA scan * Bilirubin ≤ 1.5 times normal * SGOT or SGPT ≤ 2 times normal * HIV antibody-negative * No prior malignancy except for adequately treated basal cell or squamous cell skin cancer, adequately treated noninvasive carcinoma, or other cancer from which the patient has been disease-free for at least five years * No active evidence of hepatitis B or C infection * No hepatitis B surface antigen positivity * No history of alcohol abuse * Body weight ≤ 250 pounds PRIOR CONCURRENT THERAPY: * See Disease Characteristics * Patients who have received involved field external beam therapy to area excluding lung, heart, liver and kidney are allowed, but will be evaluated on a case-by-case basis * Patients must have recovered from last therapy and should be at least four weeks from prior radiation or chemotherapy * No prior radioimmunotherapy * No prior bone marrow transplantation