OUTLINE: This is a multicenter study. Patients receive doxorubicin IV, etoposide IV, vincristine IV, and cyclophosphamide IV continuously over days 1-4. Patients also receive oral prednisone twice daily on days 1-5 and filgrastim (G-CSF) subcutaneously beginning on day 6 until blood counts recover. Treatment continues every 21 days for a maximum of 8 courses in the absence of disease progression or unacceptable toxicity. Patients are followed every 3 months for 2 years and then every 6 months for 3 years.