Key Inclusion Criteria:

DISEASE CHARACTERISTICS:

- Diagnosis of diffuse large B-cell lymphoma, meeting 1 of the following staging criteria:
o Limited stage I disease that is bulky (i.e., more than 10 cm) or with International Prognostic Index > 1
o Stage II-IV disease

- CD20-positive disease

- Paraffin-embedded tumor specimen must be available

- No active CNS lymphoma

PATIENT CHARACTERISTICS:

- ECOG performance status 0-3

- WBC > 2,500/mm^3

- Absolute neutrophil count > 1,000/mm^3 (unless due to disease in marrow)

- Platelet count > 100,000/mm^3 (unless due to disease in marrow)

- Creatinine < 2.0 mg/dL

- Bilirubin < 1.5 mg/dL (1.5-3.0 mg/dL if due to liver involvement by lymphoma)

- AST and ALT < 3 times upper limit of normal

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- LVEF > 45%

- No HIV positivity

- No other malignancy except for basal cell carcinoma of the skin or in situ carcinoma of the cervix (unless the tumor was treated with curative intent >= 2 years ago and the patient continues to be free of evidence of recurrence)

PRIOR CONCURRENT THERAPY:

- No prior chemotherapy, radiotherapy, or immunotherapy
o A prior short course (i.e., < 2 weeks) of corticosteroids allowed