In both arms, patients undergo PET/CT scans at baseline, mid-therapy, and after completion of chemotherapy. Patients with stable or progressive disease after completion of chemotherapy are removed from the study. Patients with complete response undergo observation. Patients with partial response undergo involved-field radiotherapy to any area of bulky disease at diagnosis and to any FDG-avid area on PET scan 3-4 weeks after completion of chemotherapy. These patients then undergo additional PET/CT scan at 8-10 weeks after completion of radiotherapy.