Chronic Myeloid Leukemia Coverage from Every Angle

ASH 2019: Blast Thresholds in CML and High-Risk Additional Chromosomal Abnormalities

By: Joseph Fanelli
Posted: Friday, January 3, 2020

According to findings presented at the 2019 American Society of Hematology (ASH) Annual Meeting & Exposition in Orlando, Florida (Abstract 666), high-risk additional chromosomal abnormalities appear to be strong indicators of death by blast crisis at low blast levels and may help physicians recognize end-phase chronic myeloid leukemia (CML) in patients earlier than is currently possible with present blast thresholds. Findings published by Rüdiger Hehlmann, MD, of the European LeukemiaNet (ELN) Foundation, Weinheim, Germany, and colleagues suggest that cytogenetic monitoring is indicated with signs of progressive disease and poor response to therapy.

In this study, the authors focused on 1,510 cytogenetically evaluable patients with chronic phase CML. The patients were evaluated for additional chromosomal abnormalities and blast increase. Patients were sorted into high- and low-risk cohorts. High-risk chromosomal abnormalities included +8, +Philadelphia chromosome, i(17q), +17, +19, +21, 3q26, 11q23, –7, complex), and low-risk chromosomal abnormalities included all others.

The authors found that 139 patients (9.2%) exhibited additional chromosomal abnormalities at any time before the diagnosis of blast crisis. A total of 88 patients (5.8%) had high-risk additional chromosomal abnormalities, and 51 patients (3.4%) had low-risk additional chromosomal abnormalities. These abnormalities emerged in patients after a median of 17 months. Additionally, 79 patients developed blast crisis, and 43 of 71 cytogenetically evaluable patients with blast crisis exhibited high-risk additional chromosomal abnormalities (61%).

The 3-year survival of patients after the emergence of high-risk additional chromosomal abnormalities was 48%, and it was 92% after the emergence of low-risk additional chromosomal abnormalities. At low blast levels, patients with high-risk additional chromosomal abnormalities experienced increased hazards for death, although at blast increases up to 20% to 30%, the same effect was not observed. In total, 38 patients with high-risk additional chromosomal abnormalities died. Of 36 patients with known causes of death, 26 had blast crises (72%).

Disclosure: For full disclosures of the study authors, visit

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