Combination Chemotherapy With or Without Monoclonal Antibody Therapy in Treating Patients With Stage III or Stage IV Low-Grade Non-Hodgkin's Lymphoma

Inclusion Criteria: Patients must have Stage III-IV (Ann Arbor classification) low-grade Non-Hodgkin's lymphoma Baseline measurements and evaluations must be obtained within 4 weeks prior to registration; all areas of disease (evaluable and measurable) should be recorded and mapped out in order to assess response and uniformity of response to therapy; must have at least one objective MEASURABLE disease parameter Radiographic findings are acceptable providing that clear-cut measurement can be made Abnormalities on scans may be used to document the presence of disease for staging purposes; a clearly defined, bidimensionally measurable defect or mass measuring at least 2 cm in diameter on a radionuclide or a CT scan will be acceptable as measurable disease An enlarged spleen extending at least 2 cm below the costal margin will constitute measurable disease providing that no explanation other than lymphomatous involvement is likely; for an enlarged liver to constitute the only evident measurable disease parameter, liver biopsy proof of lymphoma in the liver is required Patients must have a tissue diagnosis of low-grade malignant lymphoma obtained within 12 months prior to registration (according to the International Working Formulation) as below: ML- small lymphocytic (Category A) ML-follicular-small cleaved (Category B) ML-follicular-mixed small cleaved and large cell (Category C) Patients having both diffuse and follicular architectural elements will be considered eligible if the histology is predominantly follicular (i.e. >= 50% of the cross-sectional area); if the interval since tissue diagnosis of low-grade malignant lymphoma is > 12 months, diagnostic confirmation using either FNA or nodal biopsy is required to confirm that the histology remains in one of the eligible categories Women of child bearing potential and sexually active males are strongly advised to use an accepted and effective method of birth control No prior chemotherapy, radiotherapy, or immunotherapy No active, uncontrolled infections (afebrile for > 48 hours off antibiotics) No evidence of a previous or concurrent malignancy, with the exception of 1) treated carcinoma in situ of the cervix, 2) treated squamous cell or basal cell skin cancer OR 3) any other surgically cured malignancy from which the patient has been disease free for at least 5 years ECOG performance status 0-1 WBC > 3000/mm^3 Plts > 100,000/mm^3 Creatinine =< 1.5 mg/dl Bilirubin < 2.0 mg/dl LFTs =< 5x ULN (SGOT and Alkaline Phosphate) These lab values must be obtained within 4 weeks prior to protocol entry; patients with documented marrow involvement at the time of registration are not required to meet the hematologic parameters above Patient must give signed informed consent