Table I.

Staging classification criteria for CML [7–9]

Disease stage	ELN criteria	MDACC criteria	WHO criteria
Chronic phase	None of the criteria for accelerated phase or blast crisis	High risk Platelets > 1000 × 109/L before therapy Clonal evolution not present at diagnosis but develops during the course of therapy Low risk Blasts <10% in peripheral blood or bone marrow Basophils <20% in peripheral blood or bone marrow Clonal evolution present at diagnosis but does not progress during the course of therapy	White blood cell count ≥20 × 109/L Blasts <10% Peripheral blood basophils <20%
Accelerated phase	Blasts 15%–29% in blood or bone marrow; blasts plus promyelocytes >30% in blood or bone marrow, with blasts <30% Basophils ≥20% in blood Persistent thrombocytopenia (<100 × 109/L) unrelated to therapy	Blasts 10%–29% in peripheral blood or bone marrow Blasts plus promyelocytes ≥30% Basophils ≥20% in peripheral blood or bone marrow Platelets <100 × 109/L unrelated to therapy Persistent splenomegaly, white blood cell count > 10 × 109/L, or platelets > 1000 × 109/L unresponsive to sustained therapy	Blasts 10%–19% of white blood cells in peripheral and/or nucleated bone marrow cells Peripheral blood basophils ≥20% Persistent thrombocytopenia (<100 × 109/L) unrelated to therapy or persistent thrombocytosis (≥1000 × 109/L) unresponsive to therapy Increasing spleen size and increasing white blood cell count unresponsive to therapy Cytogenetic evidence of clonal evolution
Blast crisis	Blasts ≥30% in blood or bone marrow Extramedullary blast involvement	Blasts ≥30% in peripheral blood or bone marrow Extramedullary blastic disease	Blasts ≥20% of peripheral blood white cells or nucleated bone marrow cells Extramedullary blast proliferation Large foci or clusters of blasts in the bone marrow biopsy

Abbreviations: ELN, European Leukemia Net; MDACC, MD Anderson Cancer Center; WHO, World Health Organization