Original article http://dx.doi.org/10.3345/kjp.2012.55.3.100 Korean J Pediatr 2012;55(3):100-106 Outcome of allogeneic hematopoietic stem cell transplantation for childhood acute lymphoblastic leukemia in second complete remission: a single institution study Copyright © 2012 by The Korean Pediatric Society This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by- nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Key words: Acute lymphoblastic leukemia, Child, Second complete remission, Transplantation Eun-Jung Lee, MD, Ji Yoon Han, MD, Jae Wook Lee, MD, Pil-Sang Jang, MD, PhD, Nack-Gyun Chung, MD, PhD, Dae-Chul Jeong, MD, PhD, Bin Cho, MD, PhD, Hack-Ki Kim, MD, PhD Department of Pediatrics, The Catholic University of Korea, School of Medicine, Seoul, Korea Received: 15 September 2011, Revised: 31 October 2011 Accepted: 14 November 2011 Corresponding author: Bin Cho, MD, PhD Department of Pediatrics, Seoul St. Mary’s Hospital, The Catholic University of Korea School of Medicine, 222 Ban- po-daero, Seocho-gu, Seoul 137-701, Korea Tel: +82-2-2258-6187, Fax: +82-2-588-3589 E-mail: chobinkr@catholic.ac.kr Purpose: The survival rate for childhood acute lymphoblastic leukemia (ALL) has improved significantly. However, overall prognosis for the 20 to 25% of patients who relapse is poor, and allogeneic hematopoietic stem cell transplantation (HSCT) offers the best chance for cure. In this study, we identified significant prognostic variables by analyzing the outcomes of allogeneic HSCT in ALL patients in second complete remission (CR). Methods: Fifty-three ALL patients (42 men, 79%) who received HSCT in second CR from August 1991 to February 2009 were included (26 sibling donor HSCTs, 49%; 42 bone marrow transplantations, 79%). Study endpoints included cumulative incidence of acute and chronic graft-versus-host disease (GVHD), relapse, 1-year transplant-related mortality (TRM), disease-free survival (DFS), and overall survival (OS). Results: Cumulative incidences of acute GVHD (grade 2 or above) and chronic GVHD were 45.3% and 28.5%, respectively. The estimated 5-year DFS and OS for the cohort was 45.2±6.8% and 48.3±7%, respectively. Only donor type, i.e., sibling versus unrelated, showed significant correlation with DFS in multivariate analysis (P =0.010). The rates of relapse and 1 year TRM were 28.9±6.4% and 26.4±6.1%, respectively, and unrelated donor HSCT (P =0.002) and HLA mismatch (P =0.022) were significantly correlated with increased TRM in univariate analysis. Conclusion: In this single institution study spanning more than 17 years, sibling donor HSCT was the only factor predicting a favorable result in multivariate analysis, possibly due to increased TRM resulting from unrelated donor HSCT. 100