DISEASE CHARACTERISTICS:

• Diagnosis of diffuse B-cell lymphoma in a nodal or an extranodal site

  • CD20 and CD79 positive
  • 100% expression of Ki67 (MIB1) in all of the tumor cells OR

• Diagnosis of bone marrow replacement/leukemia comprising mature B-cell lymphoma

  • sIg and CD19 positive
  • CD34 and Tdt negative

• Patients in the low-risk group must meet at least 3 of the following criteria:

  • Normal lactate dehydrogenase (LDH) level
  • WHO performance status 0-1
  • Ann Arbor stage I or II
  • No more than 1 extranodal site (e.g., bone marrow, gastrointestinal tract, or CNS)

• Patients in the high-risk group must meet at least 2 of the following criteria:

  • Raised LDH level
  • WHO performance status 2-4
  • Ann Arbor stage III or IV
  • More than 1 extranodal site

PATIENT CHARACTERISTICS:

Age:

• 16 and over

Performance status:

• See Disease Characteristics

Life expectancy:

• Not specified

Hematopoietic:

• See Disease Characteristics

Hepatic:

• See Disease Characteristics

Renal:

• Not specified

Other:

• No mental or physical status that would preclude study
• No other disease or prior malignancy that would preclude study
• HIV negative
• Not pregnant
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• No prior chemotherapy except 1 course of preinduction chemotherapy (e.g., CHOP [cyclophosphamide, doxorubicin, vincristine, and prednisone] or a related regimen)

Endocrine therapy:

• Not specified

Radiotherapy:

• No prior radiotherapy

Surgery:

• Not specified