Patients receive EPOCH chemotherapy comprising etoposide, vincristine, and doxorubicin IV continuously on days 1-5, cyclophosphamide IV over 30 minutes on day 5, and oral prednisone on days 1-5. Patients also receive filgrastim (G-CSF) subcutaneously (SC) daily beginning on day 7 and continuing until blood counts recover. Treatment repeats every 21-28 days for at least 2 courses beyond best response or for up to 6 courses in the absence of unacceptable toxicity, disease progression, or stable disease.