Accelerated phase chronic myeloid leukemia: evaluation of clinical criteria as predictors of survival, major cytogenetic response and progression to blast phase

Background: Published criteria defining the accelerated phase in chronic myeloid leukemia are heterogeneous and little is known about predictors of poor outcome.

Methods: This is a retrospective study of 139 subjects in the accelerated phase of chronic myeloid leukemia treated with imatinib at a single center in Brazil. The objective was to identify risk factors for survival, major cytogenetic response and progression to blast phase in this population. The factors analyzed were: blasts 10-29%, basophils≥20%, platelets>1×10(6)/μL or <1×10(5)/μL and white blood cells>1×10(5)/μL in the peripheral blood, as well as clonal evolution, splenomegaly, hemoglobin<10g/dL, time between diagnosis of chronic myeloid leukemia and imatinib treatment, and hematologic toxicity.

Results: Risk factors for poor survival in multivariate analysis were Grades 3-4 hematologic toxicity (p-value=0.001), blasts 10-29% (p-value=0.023), and hemoglobin<10g/dL (p-value=0.04). Risk factors for not achieving major cytogenetic response were blasts 10-29% (p-value=0.007), hemoglobin<10g/dL (p-value=0.001), and previous use of interferon (p-value=0.032). Risk factors for progression to the blast phase were hemoglobin<10g/dL (p-value=0.005), basophils≥20% (p-value=0.023), and time from diagnosis of chronic myeloid leukemia to imatinib treatment>12 months (p-value=0.030).

Conclusion: These data indicate that patients with the above risk factors have a worse prognosis. This information can guide the therapy to be used.