Background: The total body irradiation (TBI)-based myeloablative conditioning regimen for allogeneic stem cell transplantation has been developed to overcome treatment failure and to improve overall survival of pediatric leukemia. The present study retrospectively reports the safety and success of this treatment regimen.
Objective: The objective was to report the safety and success of this treatment program based on the evaluation of effectiveness and complications from treatment, overall and disease free survival rate of patients and prognostic factors that might affect survival outcome.
Material and Method: Forty-four pediatric leukemic patients received the TBI-based myeloablative conditioning regimen for
allogeneic stem cell transplantation at Ramathibodi Hospital between 1997 and 2011. The data were evaluated for clinical
outcome.
Results: With the median follow-up period at 5.9 years (ranging from 0.3 to 16.7 years), 29 cases (65.9%) were alive, 15 cases (34.1%) died. The Kaplan-Meier estimated that the overall survival rate was 72.5% after three years, 70% after five years, and 63.0% after 10 years. The diseases free survival rates at 3, 5 and 10 years were 85.5%, 82.5%, and 82.5%, respectively. Significantly, lower survival rate was observed in patients with relapsed disease prior to transplantation and in patients with no remission of disease after transplantation.
Conclusion: The TBI-based myeloablative conditioning regimen for allogeneic stem cell transplantation can be applied to
management of selected pediatric leukemic patients.

Keywords: Total body irradiation, Myeloablative conditioning regimen, Allogeneic stem cell transplantation, Pediatric leukemia