Chronic Myeloid Leukemia and Polycythemia Vera Progression

Table 1 Accelerated and blast phase in CML and PV

	Accelerate phase^a	Blast phase
CML	Persistent or increasing white blood cell count (>10 3 × 10⁹/L) Persistent or increasing splenomegaly Persistent thrombocytosis (>1000 × 10⁹/L) Persistent thrombocytopenia (<100 × 10⁹/L) unrelated to therapy 20% or more blood basophils 10%–19% blasts in the blood or bone marrow Additional clonal chromosomal abnormalities (second Ph, trisomy 8, isochromosome 17q, trisomy 19, complex karyotype, or abnormalities of 3q26.2) Any new clonal chromosomal abnormality in Ph1 cells that occurs during therapy Tyrosine kinase inhibitor resistance^b	≥20% blasts in the bone marrow and/or peripheral blood Extramedullary blast proliferation
PV	Spent phase, post-polycythemic myelofibrosis Leucoerythroblastic blood smear Bone marrow fibrosis Decreasing blood cell counts and increasing splenomegaly Leukocytosis like in atypical CML or chronic myelomonocytic leukemia 10%–19% blasts in the blood or bone marrow	≥20% blasts in the bone marrow and/or peripheral blood Extramedullary blast proliferation

^aIn PV, acceleration is not an established term. In general use are designations as spent phase and post-polycythemic myelofibrosis
^bSee text