Analysis of risk factors influencing outcome in children with myelodysplastic syndrome after unrelated cord blood transplantation.

We describe 70 children with myelodysplastic syndrome (MDS) (refractory cytopenia (n=31) and refractory anemia with excess blasts (n=30) or blasts in transformation (n=9)) who received umbilical cord blood (UCB) transplantation with a single UCB unit and a myeloablative conditioning regimen. Approximately 20% of children had secondary MDS. Median age at transplantation was 7 years and the median follow-up was 3 years. The day-60 probability of neutrophil recovery was 76%; recovery was faster after transplantation of matched or 1-locus mismatched UCB, irradiation-containing conditioning regimen, cell dose >6 × 10(7)/kg and monosomy 7. Risks of treatment failure (recurrent disease or death) were lower in patients with monosomy 7 and transplantations after 2001. The 3-year disease-free survival (DFS) was 50% for transplantations after 2001 compared with 27% for the earlier period (P=0.018). Transplantations after 2001 occurred within 6 months after diagnosis and used UCB units with higher cell dose. DFS was highest in patients with monosomy 7 (61%) compared with other karyotypes (30%), P=0.017. These data suggest that transplantation of mismatched UCB graft is an acceptable alternative for children without a matched sibling or suitably matched unrelated adult donor.