LAUSR

With great interest, we read the recent article by Soderlund et al. in your journal describing the incidence, patient characteristics and outcome of Swedish patients with chronic myeloid leukemia (CML) in accelerated phase (AP) or blast crisis (BC) (1). The authors compared observations in a Swedish population-based cohort to published intervention trials and found similar results in patient outcome. Of note however, the authors classified their cases using the diagnostic criteria defined by the World Health Organization (WHO) (2). It is important to appreciate that the WHO (2) and European LeukemiaNet (ELN) (3) are inconsistent in their definitions of AP and BC. According to the WHO definition, CML-patients with 10-19% blasts in blood or bone marrow are considered in AP and patients with a blast rate of 20% or more are defined as in BC, whereas the ELN characterizes blast rates between 15-29% as AP and 30% or above as BC. This may confound comparisons with the referenced clinical trials as these used the ELN diagnostic criteria for inclusion (4-8). This article is protected by copyright. All rights reserved.