Rituximab and Combination Chemotherapy in Treating Patients With Stage II, Stage III, or Stage IV Diffuse Large B-Cell Non-Hodgkin's Lymphoma

OBJECTIVES: Primary * Determine the 2-year progression-free survival (PFS) rate after treatment with rituximab, ifosfamide, carboplatin, and etoposide (R-ICE) in patients with bulky stage II or stage III or IV diffuse large B-cell non-Hodgkin's lymphoma who remain positron emission tomography (PET)-positive after 3 courses of rituximab, cyclophosphamide, vincristine, doxorubicin hydrochloride, and prednisone. Secondary * Determine the proportion of mid-treatment PET-positive patients who become PET-negative after 4 courses of R-ICE. * Determine the PFS of mid-treatment PET-negative patients treated with these regimens. * Determine the overall survival of patients treated with these regimens. * Determine the toxicity of these regimens in these patients. OUTLINE: * Rituximab and Combination Chemotherapy (R-CHOP: R= Rituximab, C= Cyclophosphamide, H= Doxorubicin Hydrochloride (Hydroxydaunomycin), O= Vincristine Sulfate (Oncovin), P= Prednisone): Patients receive rituximab IV, cyclophosphamide IV, doxorubicin hydrochloride IV, and vincristine IV on day 1, and oral prednisone once daily on days 1-5. Treatment repeats every 21 days for 4 courses in the absence of disease progression or unacceptable toxicity. Patients undergo fludeoxyglucose F18 positron emission tomography (PET) scanning and conventional restaging during course 3. Based on the PET results, patients are assigned to 1 of 2 treatment groups. * Group I (PET negative): Patients receive 2 more courses of R-CHOP as above in the absence of disease progression or unacceptable toxicity. * Group II (PET positive): Patients receive Rituximab 375 mg/m2 IV Day 1, Ifosfamide 5000 mg/m2 IV over 24 hours Day 2, Carboplatin AUC 5 (max: 800 mg) IV Day 2, Etoposide 100 mg/m2 IV Days 1, 2, 3 (R-ICE), Mesna 5000 mg/m2 IV over 24 hours Day 2, and Filgrastim 5 mcg/kg/day subcutaneous (SC) Day 4 until absolute neutrophil count (ANC) recovery every 14 days for 4 courses in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed periodically for 10 years from the date of study entry. ACCRUAL: A total of 100 patients were accrued for this study.