Criteria

Modified MD Anderson Cancer Center (MDACC) criteria[40]

Subsequent to the introduction of tyrosine kinase inhibitor (TKI) therapy, many clinical trials have employed MDACC criteria for advanced-phase CML.[5] MDACC criteria and International Bone Marrow Transplant Registry (IBMTR) criteria are favored in clinical practice.

Accelerated-phase chronic myeloid leukemia (CML)

  • Peripheral blasts ≥15% and <30%

  • Peripheral blasts and promyelocytes combined ≥30%

  • Peripheral basophils ≥20%

  • Thrombocytopenia (platelet count ≤100 × 10⁹/L) unrelated to therapy

  • Cytogenetic clonal evolution

Blast-phase CML

  • ≥30% blasts in the marrow or peripheral blood

  • Extramedullary disease with localized immature blasts

International Bone Marrow Transplant Registry (IBMTR) criteria[5]

Subsequent to the introduction of TKI therapy, many clinical trials have employed IBMTR criteria.[5] IBMTR criteria and MD Anderson Cancer Center (MDACC) criteria are favored in clinical practice.

Blast-phase CML

  • ≥30% blasts in the blood, marrow, or both

  • Extramedullary infiltrates of leukemic cells

The 5th edition of the World Health Organization (WHO) classification of haematolymphoid tumours: myeloid and histiocytic/dendric neoplasms[41][42]

Most definitions of advanced phases of CML include criteria for accelerated and blast phase. However, the WHO no longer includes accelerated phase, replacing it with features associated with increased risk of progression in chronic-phase CML.[42] This is because successful treatment with TKIs has resulted in fewer patients progressing from the chronic phase.

High-risk features at diagnosis

  • 10% to 19% of blasts in bone marrow or peripheral blood (presence of lymphoblasts, even if <10%, is consistent with blast-phase disease)

  • ≥20% basophils in peripheral blood

  • Additional clonal chromosomal abnormalities in Philadelphia-positive cells (e.g., second Philadelphia chromosome, trisomy 8, -7/7q abnormalities, isochromosome 17q, complex karyotype, or 3q26.2 rearrangements)

High-risk features emerging on TKI therapy

  • Failure to achieve a complete hematologic response to the first TKI

  • Any indication of resistance to two sequential TKIs (excluding explicable causes)

  • Development of any new additional chromosomal abnormalities

  • Occurrence of compound mutations in BCR::ABL1 during TKI therapy

Blast-phase CML (if one or more is present)

  • Blasts ≥20% of peripheral blood white cells or bone marrow cells

  • Extramedullary blast proliferation

  • Increased lymphoblasts in peripheral blood or bone marrow (optimal cutoff unclear)

International consensus classification of myeloid neoplasms and acute leukemias[43]

Accelerated-phase CML

  • 10% to 19% of blasts in bone marrow or peripheral blood

  • ≥20% basophils in peripheral blood

  • Additional clonal cytogenetic abnormalities in Philadelphia-positive cells (e.g., second Philadelphia chromosome, trisomy 8, isochromosome 17q, trisomy 19, complex karyotype, or abnormalities of 3q26.2)

Blast-phase CML

  • ≥20% blasts in bone marrow or peripheral blood

  • Myeloid sarcoma (i.e., extramedullary blast proliferation)

  • Presence of morphologically apparent lymphoblasts (>5%) in peripheral blood or bone marrow warrants consideration of lymphoblastic crisis

See Blast crisis.

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