Summary:The aim of this study was to compare toxicity and efficacy of total body irradiation (TBI), cyclophosphamide (CY) and etoposide (E) (TBI/CY/E) vs busulfan, melphalan and thiotepa (Bu/Mel/T) in patients receiving autologous stem cell infusion (ASCI) for malignant lymphoma (NHL). Between September 1990 and July 1998, 351 patients with NHL were treated with TBI/CY/E (n = 221) or Bu/Mel/T (n = 130) followed by ASCI. Patients in first, or second remission, first responding or untreated relapse were defined as having less advanced disease before transplantation. The median follow-up was 5 years (range 1-9) and 3.5 years (1-6) for patients receiving TBI/CY/E and Bu/Mel/T, respectively. The cumulative probabilities of survival, event-free survival (EFS) and relapse at 5 years were 44%, 32%, 49% following TBI/CY/E and 42%, 34% and 42% following Bu/Mel/T. The probability of EFS at 5 years for patients who had prior dose-limiting radiation (n = 59) was 32% after Bu/Mel/T therapy. Transplant-related mortality was 16% for TBI/CY/E and 21% for Bu/Mel/T. In univariate and multivariate analyses, more advanced disease status was associated with poor outcome ( but almost all of these patients relapse and die, despite salvage treatment. Thirty to 60% of patients with aggressive NHL can be cured with intensive chemotherapy. However, the 2-year survival for patients who fail or relapse after induction chemotherapy is only 5 to 10%. 1 High-dose chemotherapy (HDC) supported with autologous stem cell infusion (ASCI) has proven efficacy in patients with first or subsequent chemotherapy-sensitive relapse, as well as in those patients who fail induction chemotherapy. 2 Radiation-based and chemotherapy-only preparative regimens have been evaluated in patients with NHL. [2][3][4][5][6][7][8][9][10][11][12][13][14][15] However, the superiority of a specific HDC conditioning regimen for NHL has not been proven and few comparisons between regimens have been reported. [12][13][14][15] The Fred Hutchinson Cancer Research Center (FHCRC) has evaluated both radiation-based and chemotherapy-only conditioning regimens for the treatment of lymphomas. Phase II studies of both approaches have previously been published. 3,8,[16][17][18] High-dose fractionated total body irradiation (TBI), cyclophosphamide (CY) and etoposide (E) (TBI/CY/E) followed by ASCI was evaluated in patients with NHL (n = 43) and Hodgkin's disease (n = 10) who had failed to achieve a complete response after conventional chemotherapy or who had chemosensitive relapse. The 2-year Kaplan-Meier (KM) probabilities of survival, event-free survival (EFS) and relapse were 54%, 45% and 43%, respectively. The treatment-related mortality (TRM) was 17%. 16 Twenty-three patients with NHL and 17 with Hodgkin's disease were treated with the high-dose regimen of Busulfan (Bu), Melphalan (Mel) and Thiotepa (T) (Bu/Mel/T). The 2-year KM estimates of survival, EFS and relapse were 60%, 46% and 31%, respectively with a transplant-related mortality of 17%. 18 Randomized trials comparing the eff...