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.