OBJECTIVES: I. Assess the treatment-related neurologic and hematologic toxicities of patients aged 65 years and over with intermediate- or high-grade non-Hodgkin's lymphoma randomized to CHOP (cyclophosphamide, doxorubicin, vincristine, prednisolone) vs. MCOP (mitoxantrone, cyclophosphamide, vincristine, prednisolone). II. Compare the survival rate in these patients.