Radiation Therapy in Relapsed or Refractory Non-Hodgkin's Lymphoma Who Have Undergone Stem Cell Transplantation

RATIONALE: Radiation therapy uses high-energy x-rays to damage tumor cells. It is not yet known if giving radiation therapy after stem cell transplantation is more effective than stem cell transplantation alone in treating relapsed or refractory non-Hodgkin's lymphoma. PURPOSE: Randomized phase III trial to determine the effectiveness of radiation therapy in treating patients who have relapsed or refractory non-Hodgkin's lymphoma and have undergone autologous stem cell transplantation.

OBJECTIVES: * Compare the 3-year progression-free survival of patients with relapsed or refractory aggressive non-Hodgkin's lymphoma treated with high-dose chemotherapy and autologous hematopoietic stem cell transplantation with or without involved-field radiotherapy. * Compare the overall survival of patients treated with these regimens. * Compare 3-year progression-free disease within and outside radiotherapy fields in patients treated with these regimens. * Compare quality of life of patients treated with these regimens. * Compare the toxic effects of these regimens in these patients. OUTLINE: This is a randomized, multicenter study. Patients are stratified according to response to pre-salvage chemotherapy (primary refractory disease vs relapse), response to post-salvage chemotherapy (complete/unconfirmed complete vs partial), and participating center. Within 6-8 weeks after completion of autologous hematopoietic stem cell transplantation, patients are randomized to 1 of 2 treatment arms. * Arm I: Patients undergo involved-field radiotherapy (IFRT) 5 days a week for 3-5 weeks in the absence of unacceptable toxicity. * Arm II: Patients undergo observation only. Quality of life in arm I is assessed at baseline, on day 1 of IFRT, at weeks 2 and 4 during IFRT, at 1 month, 4 months, every 3 months for 2 years, every 6 months for 1 year, and then annually for 2 years. Quality of life in arm II is assessed at baseline, 1 month, 2 months, every 3 months for 2 years, every 6 months for 1 year, and then annually for 2 years. Patients are followed at 1 month, every 3 months for 2 years, every 6 months for 1 year, and then annually for 2 years. PROJECTED ACCRUAL: A total of 230 patients (115 per treatment arm) will be accrued for this study within 4.2 years.