- Arm II: Patients receive one additional course of CHOP/CHOP-R followed by filgrastim (G-CSF), sargramostim (GM-CSF), or other colony-stimulating factors used singly or in combination according to center preference. PBSC are harvested and selected for CD34+ cells. Patients under age 61 receive one of two preparative regimens: a total body irradiation (TBI)-based regimen comprising irradiation administered twice daily on days -8 to -5, etoposide IV over 4 hours on day -4, and cyclophosphamide IV over 1 hour on day -2 OR carmustine IV over 2 hours on days -6 to -4 and etoposide and cyclophosphamide as in the TBI-based regimen. Patients age 61 to 65 receive the augmented regimen comprising carmustine, etoposide, and cyclophosphamide as above. Patients receive involved field radiotherapy prior to the preparative regimen only if there is biopsy-proven residual bulk disease and at the discretion of the center. PBSC are reinfused 36-48 hours after completion of cyclophosphamide. If both bone marrow and PBSC are harvested, bone marrow is reinfused on day 0 and then PBSC are reinfused either the same day or the following day.