It may be time to review and update treatment strategies for patients with chronic myeloid leukemia (CML) who are diagnosed in accelerated phase (AP) or blast crisis (BC). Most patients with CML are diagnosed in chronic phase, and subsequently, there are little published data on the prognosis of patients diagnosed in AP or BC. In a study published in the American Journal of Hematology, researchers aimed to identify prognostic factors for survival of patients with CML diagnosed in AP or BC.

The researchers enrolled 283 patients (median age, 51 years; range, 18-89) who were diagnosed in AP. The cohort included 151 male (53%) and 132 female (47%) patients, and nearly all patients had been treated with tyrosine kinase inhibitors. After a median observation time of 5.8 years, 115 of the 283 patients had died.

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Median survival was 8.2 years, but there were significant differences between patients diagnosed with CML in AP and patients diagnosed with CML in BC. Median survival for patients with CML diagnosed in BC was 1.8 years after a median observation time of 6.0 years. Median survival was not reached for patients with CML diagnosed in AP.

Clinicians refer to the European Leukemia Net and the World Health Organization staging classification systems when treating patients diagnosed with CML in AP or BC. However, there is debate over the definition of CML‐BC. The World Health Organization criteria employ a cutoff of 20% blasts while the European Leukemia Net criteria employ a cutoff of 30% blasts.

In this study, the hazard ratio (HR) for patients with more than 30% blasts compared with patients with 20% to 29% blasts was 1.32 (95% CI, 0.7‐2.6). Individuals with 20% to 29% blasts were found to have a significantly higher risk for death compared with patients who had less than 20% blasts (HR, 2.24; 95% CI, 1.2‐4.0; P =.008).

The researchers concluded that blast count was the most important prognostic factor, although age, hemoglobin, basophils, and other chromosomal aberrations also demonstrated prognostic value. Furthermore, they wrote, “It is our perception that a 2-phase rather than a 3-phase categorization of de novo patients is appropriate, and that a 20% blast cutoff could be involved in a new definition.”

Disclosures: Some authors have declared affiliations with the pharmaceutical industry. Please refer to the original study for a full list of disclosures.

Reference

1.     Lauseker M, Bach K, Turkina A, et al. Prognosis of patients with chronic myeloid leukemia presenting in advanced phase is defined mainly by blast count, but also by age, chromosomal aberrations and hemoglobin [published online August 27, 2019]. Am J Hematol. doi:10.1002/ajh.25628