Presence of peripheral blasts in refractory anemia and refractory cytopenia with multilineage dysplasia predicts an unfavourable outcome

The World Health Organization (WHO) assigns myelodysplastic syndrome (MDS) to RA/RCMD/RARS/RSCM/5q- syndrome, if medullary blasts are < 5% and peripheral blast (PB) count < 1%. In 1103 patients with these diagnoses, we analysed Survival and risk of AML evolution depending on the presence of PB. Median survival in the group with 1% PB (n = 74) was significantly lower as compared to those without PB (20 versus 47 months, p < 0.00005). Cumulative risk of AML was significantly higher in patients showing PB (P < 0.00005). Median survival of patients with PB was not different from that of RAEB I. We therefore propose to consider patients with PB, regardless of medullary blast, as RAEB I. (c) 2007 Elsevier Ltd. All rights reserved.