- Arm I: Patients receive CHOP (or CHOP plus rituximab [CHOP-R]) as above. Treatment repeats every 3 weeks for 3 additional courses. After completion of chemotherapy, patients are encouraged to undergo harvest of peripheral blood stem cells (PBSC) for possible use at time of relapse. After completion of 8 courses, patients receive no additional therapy until disease progression or biopsy-proven disease.