Inclusion Criteria

DISEASE CHARACTERISTICS:

- Patients must have biopsy-proven diffuse large B-cell lymphoma (DLBCL)

- Adequate sections or a paraffin block from the original diagnostic specimen must
be submitted for review by the lymphoma pathology group

- Lymphoma must express CD20 antigen by either flow cytometry using anti-CD20
antibodies or by immunoperoxidase staining of paraffin sections

- Patients with primary mediastinal lymphoma or testicular lymphoma are not
eligible

- Patients must have non-bulky stage I or II disease by Ann Arbor classification

- This staging excludes FDG-PET evaluation

- Patients who have stage I or II non-bulky disease on diagnostic CT scan, but are
upstaged to stage III or IV based on FDG-PET evaluation, are also eligible

- Patients must have a diagnostic quality contrast-enhanced CT scan of the chest,
abdomen, and pelvis AND baseline FDG-PET scan performed within 28 days prior to
registration

- Low-resolution "localization" CT scans performed as part of a combined PET/CT
scan are not adequate for enrollment or response determination on this protocol

- If a patient has an allergy to CT contrast, then a non-enhanced CT will be
acceptable

- Patients must not have clinical evidence of central nervous system (CNS) involvement
by lymphoma

- Any laboratory or radiographic tests performed to assess CNS involvement must be
negative and must be performed within 42 days prior to registration

- Patients may have either measurable or evaluable limited-stage DLBCL

- Patients rendered free of measurable or evaluable disease by virtue of biopsy
(resection) are also eligible

- If patient has measurable disease it must be documented on the Lymphoma Baseline
Tumor Assessment Form (Form #15187)

- All measurable disease must be assessed within 28 days prior to registration

- Patients with non-measurable disease in addition to measurable disease must have
all non-measurable disease assessed within 42 days prior to registration

- Patients must have a unilateral or bilateral bone marrow biopsy performed within 42
days prior to registration

PATIENT CHARACTERISTICS:

- Zubrod performance status 0-2

- ANC ≥ 1,000/mm³

- Platelet count ≥ 100,000/mm³

- Total bilirubin ≤ 2 times upper limit of normal (ULN) (unless due to Gilbert
syndrome)

- Patients must not be pregnant or nursing

- Women/men of reproductive potential must have agreed to use an effective
contraceptive method during the study period

- Patients must not be known to be HIV-positive

- No other prior malignancy is allowed except for the following:

- Adequately treated basal cell or squamous cell skin cancer

- In situ cervical cancer

- Adequately treated stage I or II cancer from which the patient is currently in
complete remission

- Any other cancer from which the patient has been disease-free for 5 years

PRIOR CONCURRENT THERAPY:

- Patients must not have received prior chemotherapy, radiotherapy, or antibody therapy
for lymphoma