Inclusion Criteria:

   - Previously untreated patients with DLBCL of the breast.

   - Patients must have CD20 positive tumors.

   - Stage IE or IIE.

   - Must have at least one objective measurable or evaluable disease. Baseline
   measurements and evaluations must be obtained within 4 weeks of registration to the
   study.

   - Patients must not have historical or radiographic evidence of CNS metastasis including
   previously treated, resected or asymptomatic brain lesions or leptomeningeal
   involvement.

   - Patients must have an ECOG performance status 0-2.

   - Patients must have adequate organ function as evidenced by the following laboratory
   studies (within 2 weeks prior to registration):

      - Creatinine Clearance >= 50 ml/min

      - Total bilirubin <= 2.0 mg/dl and AST <= 2 x upper limit of normal. If documented
      hepatic involvement with lymphoma, total bilirubin can be <= 3 x *ULN, and AST <=
      5 x ULN.

      - Absolute neutrophil count >= 1500/mm3 and platelet count >= 100,000/mm3. If
      documented bone marrow involvement with lymphoma, absolute neutrophil count >=
      500/mm^3 and platelet count >= 50,000/mm^3.

   - Patients must be age >= 18 years.

   - Women must not be pregnant or breast feeding due to potential harmful effects to the
   fetus/baby. Women of childbearing potential and sexually active males are strongly
   advised to use an accepted and effective method of contraception.

   - Patients must not have an active infection requiring parental antibiotics.

   - Patients with known HIV infection are excluded.

   - Patients must have a normal left ventricular ejection fraction to be eligible.