Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Chronic myeloid leukemia/other leukemia


1

What is the chromosomal abnormality associated with chronic myeloid leukemia?

The Philadelphia chromosome—or t(9;22)(q34.1;q11.2) resulting in a BCR-ABL1 fusion gene—is the hallmark of 90% to 95% of chronic myeloid leukemia (CML) cases. The remaining cases consist of variant and cryptic translocations that also result in the characteristic BCR-ABL1 fusion gene.

2

What should be included in the initial evaluation of a patient with suspected CML?

  • Spleen size (below costal margin) on examination

  • Complete blood count (CBC) with differential

  • Qualitative reverse transcription polymerase chain reaction (RT-PCR) for BCR-ABL

  • Bone marrow aspirate (BMA) and biopsy for morphology, karyotyping, and fluorescent in situ hybridization (FISH)

3

Describe the three phases of CML.

The three phases are chronic phase (CP), accelerated phase (AP), and blast phase (BP). There is no universally agreed on definition for AP- or BP-CML. The recommendation by the Children’s Oncology Group (COG) is to follow the classification by the World Health Organization (WHO; Table 32.1 ).

Table 32.1
Classification of Three Phases of CML by the World Health Organization
Chronic phase: Presence of all of the following criteria Accelerated Phase: Presence of any of the following criteria Blast Phase: presence of any of the following criteria
Less than 10% blasts in peripheral blood or bone marrow 10%–19% blasts in peripheral blood or bone marrow ≥20% blasts in peripheral blood or bone marrow
Does not meet definition for accelerated or blast phase Persistent or increasing WBC (> 10 × 10 9 ) unresponsive to therapy Extramedullary blast proliferation
Persistent thrombocytosis (>1000 × 10 9 ) unresponsive to therapy or persistent thrombocytopenia (<100 × 10 9 ) unrelated to therapy
Blood basophils ≥20% in peripheral blood
Persistent or increasing splenomegaly, unresponsive to therapy
Additional clonal chromosomal abnormalities in Ph + cells at diagnosis, including major route abnormalities (second Ph chromosome, trisomy 8, isochromosome 17q, trisomy 19), complex karyotype, and abnormalities of 3q26.2
Any new clonal chromosomal abnormality in Ph + cells that occurs during therapy
Provisional response criteria to TKI: Failure to achieve complete hematological response to first TKI; any hematological, cytogenetic, or molecular indications of resistance to two sequential TKI treatments; or occurrence of two or more mutations in BCR-ABL fusion gene during TKI therapy
CML , Chronic myeloid leukemia; TKI , tyrosine kinase inhibitor; WBC , white blood cell.

4

Is there is a curative therapy for CML, and what is its role?

Stem cell transplant (SCT) was the only curative therapy for CML before tyrosine kinase inhibitors (TKIs) were introduced. Nevertheless, with the expansion of Food and Drug Administration (FDA)–approved TKIs for childhood CML, and their relatively safe profile compared with the potential risks and long-term toxicities of SCT, TKIs have replaced SCT as the primary treatment. There is no clear criteria for SCT, but it can be considered for the following conditions: BP or AP (either at diagnosis or as a progression from CP), failure of multiple TKIs, or significant toxicity from TKIs.

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here

Related Posts