Optimizing Results of Unrelated Donor Hematopoietic Stem Cell Transplantion in Developing Countries: Young Age and Early Disease as Positive Factors for Survival.

Introduction: Unrelated donor hematopoietic stem cell transplantation (HSCT) has been carried out in Brazil since 1995, with an increasing number of procedures among the transplant centers. Evaluating this experience is important to improve the outcomes of this therapeutic modality. The aim of this study is to assess risk factors for survival in 125 patients who underwent unrelated donor HSCT for malignant diseases.

Material and methods: 125 patients with malignant diseases who received unrelated donor HSCT between july/95 and june/2005 in a single institution in Brazil were analyzed. Kaplan-Meier curves were used to estimate overall survival, log-rank test for comparison of continuous variables and Fisher exact test for categorical variables. Cox proportional hazard model was used for analyzing risk factors for survival. Analyzed risk factors: sex, age, acute graft-versus-host-disease (a-GVHD) grades II-IV, extensive chronic (c) GVHD, diagnosis, stage of disease, source of stem cells, number of infused cells/Kg and HLA matching. Median age was 17 years (range 1–55), male (n=78) and female (n=44).

Diseases: CML (n=46), AML/MDS (n=40), ALL (n=34), other (n=5). Source of stem cells: bone marrow (n=95), umbilical cord blood (n=30). ATG or ALG containing regimens were used in 25 patients. Advanced disease was detected in 66 patients (53%) and was defined as CML in advanced phases, AML and ALL ≥ second clinical remission (CR2), relapsed or refractory.

Results: Acute GVHD II-IV was observed in 51 (41%) patients and extensive c-GVHD in 32 (26%). Main death causes: a-GVHD (9%), c-GVHD (13%), infections (41%) and relapse (27%). Estimated overall survival (OS) in 10 years was 40%, with a median survival of 189 days. Sex, diagnosis, stem cell source, type of conditioning, number of infused cells/Kg and HLA matching did not influenced survival. OS in 10 years was higher in patients with early stage disease compared to advanced diseases (55% × 20%; p=.0005) and in patients under 18 years of age compared to those ≥ 18 years-old (60% × 20%; p=.0012). The presence of extensive c-GVHD had a positive influence in OS (OR 0,1758 – 0,9092).

Conclusions:

1. The OS in 10 years was 40% for this group of patients.

2. Patients in early stage disease and under 18 years of age have a higher OS in 10 years (55% and 60% respectively).

3. Extensive c-GVHD had a positive impact in survival, probably due to graft versus leukemia effect.