OBJECTIVES: I. Assess the response to CHOD (cyclophosphamide/doxorubicin/vincristine/ dexamethasone) and BVAM (carmustine/vincristine/cytarabine/methotrexate) plus whole-brain radiotherapy in patients with primary central nervous system non-Hodgkin's lymphoma (PCNSL). II. Assess the toxic effects associated with this treatment. III. Assess the survival of patients with PCNSL receiving this treatment. IV. Investigate the frequency of systemic involvement at follow-up. V. Identify factors that appear to be associated with outcome.