Abstract

Introduction: Chronic myeloid leukemia (CML) accounts for 2–3% of the leukemias in childhood. The only potential curative treatment is allogeneic hematopoietic stem cell transplantation (HSCT), although promising results achieved with imatinib mesylate in adults substantiate its use as a therapeutic alternative for children. The aim of this study is to analyze the outcomes of HSCT in pediatric patients regarding overall survival (OS) and main causes of death.

Materials and methods: Retrospective analysis of children aged 1–17 years, diagnosed with CML who underwent HSCT in a single institution in Brazil between jan/1984 and aug/2005. Survival was estimated by Kaplan-Meier curves. Log Rank test was used for comparison of continuous variables.

Results: Fifty patients were assessed, 31 male and 19 female. Median age of 13,5 years (1–17). Forty one patients (82%) were in first chronic phase (CP1) and 9 in advanced phases. The interval between diagnosis and HSCT had a median time of 17,5 months (5–84). The source of stem cells was bone marrow in 44 patients (88%), umbilical cord blood in 5 (10%) and peripheral blood stem cell in 1 (2%). Thirty nine patients (78%) underwent related HSCT and 11 (22%) unrelated donor HSCT. Conditioning regimens: busulfan and cyclophosphamide in 35 patients (70%) and TBI containing regimens in 15 (30%). Complete engraftment occurred in 82% of the transplants. Acute (a) graft-versus-host-disease (GVHD) grades II–IV occurred in 44% of the patients, with 20% grade IV. Extensive chronic (c) GVHD occurred in 15/40 patients (38%). Fifteen patients (32%) relapsed after HSCT. Mortality in the study population was 48% and the main causes of death were: relapse in 6 patients (25%), a-GVHD in 6 (25%) and c-GVHD in 4 (17%). Estimated OS in 20 years was 50%, with a median survival of 1926 days. When analyzed separately, patients in CP1 who received related HSCT and immuneprophilaxis with three drugs (steroids, cyclosporine and methotrexate) had an estimated OS in 20 years of 70%.

Conclusions:

  1. Long term follow up of these children with CML who underwent allogeneic HSCT demonstrate an OS of 50%, reaching 70% in low risk patients.

  2. Main causes of death were relapse, acute and chronic GVHD.

Disclosure: No relevant conflicts of interest to declare.

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