 This study originally involved 2 different study drug regimens, R-CHOP and R-HCVAD. R-CHOP is made up of rituximab, cyclophosphamide, vincristine, and prednisone, and is the most common treatment for patients with non-Hodgkins lymphoma. This combination was compared with R-HCVAD, which is made up of rituximab, doxorubicin, cyclophosphamide, vincristine, and dexamethasone. 