blast crisis in CML

Q: Blast crisis of Chronic Myeloid Leukemia (CML) is? (select one)

A) ≥20 percent blasts in peripheral blood or bone marrow

B) ≥30 percent blasts in peripheral blood or bone marrow

Answer: A

The objective of this question is to underline the new threshold of blast crisis in CML. Previously, blast crisis has been defined as ≥30 percent blasts in the bone marrow. In 2017, the World Health Organization (WHO) established the definition of blast crisis with presence of one of the following:

● ≥20 percent blasts in peripheral blood or bone marrow

● Extramedullary proliferation of blasts (ie, myeloid sarcoma)

Scientific significance: While reviewing the systemic review and/or meta-analyses, a change of definition may create a confounder or bias in establishing the conclusion.

#oncology

#clinical research

References:

1. WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues, revised 4th edition, Swerdlow SH, Campo E, Harris NL, et al. (Eds), International Agency for Research on Cancer (IARC), Lyon 2017.

2. Cortes JE, Talpaz M, O'Brien S, et al. Staging of chronic myeloid leukemia in the imatinib era: an evaluation of the World Health Organization proposal. Cancer 2006; 106:1306.

3. Hehlmann R. How I treat CML blast crisis. Blood 2012; 120:737.