Blast crisis refers to the transformation of chronic myeloid leukemia (CML) from the chronic or accelerated phase to blast phase.
Blast phase of CML may be discovered incidentally on complete blood count or when assessing patients with symptoms and signs such as fever, fatigue, malaise, weight loss, anemia, thrombocytopenia, or splenomegaly.
Diagnosis of the blast phase of CML is usually confirmed by the percentage of blast cells (e.g., ≥20% [World Health Organization criteria] or ≥30% [MD Anderson Cancer Center and the International Bone Marrow Transplant Registry criteria]) in the peripheral blood or bone marrow. Diagnosis of CML requires the presence of the Philadelphia chromosome (a genetic mutation that results in the oncogenic BCR-ABL fusion gene).
Tyrosine kinase inhibitors are paramount in treatment. Allogeneic stem cell transplant must follow due to rapid relapse.
Blast crisis refers to the transformation of CML from the chronic or accelerated phase to blast phase.
The blast phase of CML is diagnosed by the percentage of blast cells (≥20% by WHO criteria; ≥30% by MD Anderson Cancer Center and the International Bone Marrow Transplant Registry criteria) in the peripheral blood or bone marrow, or the presence of an extramedullary accumulation of blast cells, or large foci or clusters of blasts in the bone marrow biopsy.
CML is diagnosed by the presence of the Philadelphia chromosome (a genetic mutation that results in the oncogenic BCR-ABL fusion gene).
History and exam
Key diagnostic factors
- night sweats
- abnormal/excessive bleeding
- bone pain
Other diagnostic factors
- weight loss
- petechiae, ecchymoses, or easy bruising
- abdominal pain
- visual changes
- focal neurologic signs
- confusion or stupor
- history of chronic myeloid leukemia (CML)
- exposure to alkylating chemotherapeutic agents
- exposure to ionizing radiation
1st investigations to order
- CBC and differential
Investigations to consider
- peripheral blood smear
- bone marrow aspiration and biopsy
- fluorescence in situ hybridization
- quantitative reverse-transcriptase polymerase chain reaction
- flow cytometry
- T315I gene mutation analysis
- HLA1 testing
- serum leukocyte alkaline phosphatase
- serum vitamin B12
lymphoid blast crisis
myeloid blast crisis
biphenotypic blast crisis
suboptimal response to initial treatment
partial hematologic response or second chronic phase
transplant failure or recurrence post-transplant
Carlos Palacio, MD, MPH, FACP
Professor of Medicine
University of Florida College of Medicine
CP declares that he has no competing interests.
Marwan E. Shaikh, MD
College of Medicine
Division of Hematology and Oncology
Mayo Clinic Jacksonville
MES declares that he has no competing interests.
Dr Carlos Palacio and Dr Marwan E. Shaikh would like to gratefully acknowledge Fauzia Rana, a previous contributor to this topic.
FR declares that she has no competing interests.
Danilo Perrotti, MD, PhD
Assistant Professor of Human Cancer Genetics
Ohio State University
DP declares that he has no competing interests.
- Organ-specific or systemic infection (bacterial, fungal, viral)
- Leukemoid reaction
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- Chronic myeloid leukemia
- European LeukemiaNet 2020 recommendations for treating chronic myeloid leukemia
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