Total Body Irradiation (TBI) Based Versus Chemotherapy-Based Preparative Regimens Before Autologous Stem Cell Transplant for Non-Hodgkin’s Lymphoma.

OBJECTIVES: The optimum high dose preparative regimen for non-Hodgkin lymphoma (NHL) patients undergoing autologous stem cell transplantation (ASCT) is unknown. We compared the radiation-based regimen of cyclophosphamide, etoposide and 12 Gy total body irradiation (CY/E/TBI) to carmustine, etoposide, cytarabine and melphalan (BEAM) in NHL patients who received ASCT. We investigated acute and long-term toxicities, disease free survival (DFS), overall survival (OS) of these two regimens.

METHODS: A historical cohort study was performed at a provincial cancer centre. Cause specific survival was determined with the Kaplan-Meier method. Survival between groups was compared using the log-rank test.

RESULTS: From Mar-1991 to Sep-2005, 79 patients received CY/E/TBI (n=32) or BEAM (n=47). Histology was indolent in 30 and aggressive in 49 patients. Cell source was bone marrow in six and 73 received peripheral blood progenitor cells. Prior to ASCT, ten patients were in complete remission, 47 had chemo-sensitive disease and 22 had chemo-resistant disease. There were only two cases of interstitial pneumonitis, with one in each preparative regimen group. There were six transplant related deaths; two in the BEAM group and four were in TBI group. The TBI based group has a higher mean mucosits score (p=0.03). Five year DFS was 47% and 51% in the TBI and BEAM groups, respectively (p=0.41). Five year OS was 50% and 64% for the TBI and BEAM based groups (p=0.07). Multivariate analyzes revealed that patients with more advanced disease and raised LDH at ASCT independently predicted inferior DFS. There was one case of acute myeloid leukemia and two of prostate cancer, all of whom were in the TBI group.

CONCLUSIONS: In this study, a 12 Gy TBI-based regimen resulted in a similar DFS but a trend toward poorer OS and higher second malignancies than a BEAM-based regimen. However, there did not appear to be excess pulmonary acute toxicities in the TBI based group.