OBJECTIVES: I. Determine the toxicity of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) with either interferon alfa or rituximab in patients with stage III or IV high risk indolent or intermediate B-cell lymphoma. II. Determine the objective tumor response rate and duration of response for these regimens in these patients. III. Determine the failure free survival and overall survival for these patients on these regimens. IV. Compare the response rate and survival rate of these patients on these regimens to similar patients treated in published studies. V. Compare the toxicities of these regimens in these patients. VI. Determine the quality of life of these patients on these regimens.