Comparison of Different Conditioning Regimens in Allogeneic Hematopoietic Stem-Cell Transplantation Shows Superiority of Total Body Irradiation-Based Regimen for Younger Patients With Acute Leukemia: A Nationwide Study

Recognizing the paucity of comparative data on different conditioning regimens for hematopoietic stem-cell transplantation in Asian population, we conducted a study of 1562 patients undergoing myeloablative conditioning (MAC) and 2693 patients undergoing non-MAC (NMC). We found that (1) despite the possible selection bias, MAC is associated with decreased late-phase mortality, (2) among MAC regimens, total body irradiatione based conditioning leads to better outcomes for all acute leukemias in younger patients, and (3) antithymocyte globulin use confers benefits when added to NMC regimens without compromising survival outcomes. Background: The optimal the conditioning regimens for allogeneic hematopoietic stem-cell transplantation, especially for East Asian patients, remains unknown. Patients and Methods: We collected and analyzed clinical and survival data of 4255 patients from the Korean National Health Insurance Claims Database. Results: Between 1562 myeloablative conditioning and 2693 nonmyeloablative conditioning groups, the overall survival was not statistically different. However, in the myeloablative conditioning group, the overall survival of the total body irradiationebased regimen was better than that of chemotherapy-alone regimen (P =.005). In subgroup analysis, the superiority of the total body irradiationebased regimen was especially prominent in acute leukemia (P =.012 for acute myeloid leukemia; P =.005 for acute lymphoblastic leukemia) and for younger patients (< 50 years old vs. > 50 years old, P =.015). Conclusion: Total body irradiation combination might be the best conditioning regimen for young patients undergoing hematopoietic stem-cell transplantation for acute leukemias in Korea.