Re-evaluation of refractory anemia with excess blasts in transformation

The category 'refractory anemia with excess blasts in transformation (RAEBt )' consists of two sub-sets, one group is categorized based on the percenta ge of blasts in the marrow (greater than or equal to 20%) and other is base d on the percentage of blasts in the peripheral blood (greater than or equa l to 5%). We separated RAEBt patients based on these two criteria and compa red hematologic and clinical relevance to assess the reasonable basis for t he new classification. All RAEBt patients showing peripheral blood (PB) bla sts of ! 5% were re-classified as RAEB by the WHO classification. This subs et of RAEBt patients had lower percentages of bone marrow (BM) blasts, and notably they showed frequent complex cytogenetic abnormalities, including - 5/5q- and/or -7/7q-. Moreover, the RAEBt patients of this group had shorter survivals compared to RAEBt patients with BM blasts between 20 and 30%. We next assessed hematologic and clinical relevance between refractory anemia with excess blasts (RAEB) and RAEBt patients with PB blasts of 5%. Except for the percentage of blasts in the PB (P = 0.0037) and BM (P = 0.0073), th ere was no significant difference in hematologic or clinical features betwe en RAEB patients with BM blasts of greater than or equal to 11% and RAEBt p atients with PB blasts of 5%. When MDS patients with PB blasts of !: 5% (RA EBt by the FAB classification) were included as RAEB-H based on the "MDS 20 00 classification', there was a high frequency of patients with complex chr omosome changes, involving 5q and 7q, with significant poorer outcome compa red to those with RAEB-I. Although it is still controversial whether MDS pa tients with BM blasts 20% or more should be considered as acute leukemia, t he utilization of the 'MDS 2000 classification' might be useful to designat e MDS patients diagnosed based on the percentage of blasts in the periphera l blood. (C) 2001 Elsevier Science Ltd. All rights reserved.