 Patients then receive standard R-CHOP or an alternative regimen comprising rituximab IV over 3-6 hours, cyclophosphamide IV over 30 minutes, doxorubicin IV over 5 minutes, and vincristine IV over 5 minutes on day 1 and oral prednisone once daily on days 1-5. Treatment repeats every 14-21 days for up to 4 courses in the absence of unacceptable toxicity. 