OBJECTIVES: I. Determine the efficacy of high-dose cyclophosphamide/etoposide/cisplatin in patients with intermediate- or high-grade non-Hodgkin's lymphoma who have failed primary combination chemotherapy but still respond to conventional-dose DHAP (dexamethasone/cytarabine/cisplatin) and are not candidates for bone marrow transplantation. II. Determine the toxicity of the intensification chemotherapy regimen in this group of patients.