OBJECTIVES: I. Compare the remission induction rates and toxicity of chlorambucil plus dexamethasone with or without idarubicin in patients with stage II-IV low grade non-Hodgkin's lymphoma. II. Assess the additional value of a period of consolidation/maintenance treatment utilizing low dose interferon alfa or standard dose interferon alfa versus no further treatment in relationship to the duration of event-free survival in these patients.