Does CML Cause Neutropenia?
No, chronic myeloid leukemia (CML) at diagnosis typically presents with neutrophil leukocytosis (elevated neutrophils), not neutropenia. 1
CML Presentation at Diagnosis
CML in chronic phase characteristically features:
- Marked leukocytosis with mature neutrophilia - white blood cell counts often exceed 100 × 10⁹/L with neutrophils comprising the predominant cell type 1
- Thrombocytosis (elevated platelets) is common 1
- Basophilia is a typical finding 1
- Bone marrow hypercellularity due to proliferation of myelopoiesis in all stages of maturation with predominance of mature forms 1
The disease is fundamentally a myeloproliferative disorder, not a cytopenic condition at presentation. 1
When Neutropenia Occurs in CML Patients
Treatment-Induced Myelosuppression
Neutropenia in CML patients is almost exclusively a consequence of tyrosine kinase inhibitor (TKI) therapy, not the disease itself. 1
The mechanism involves:
- Suppression of the leukemic clone combined with inhibition of residual normal hematopoiesis, which is greatly reduced at diagnosis 1
- Delayed recovery of normal stem and progenitor cells that need time to re-populate the bone marrow after being suppressed by the malignant clone 1
Incidence of TKI-Induced Neutropenia
First-line therapy neutropenia rates (grade 3/4): 1
- Imatinib 400 mg daily: 17.3% of patients
- Dasatinib 100 mg daily: 19.4% of patients
- Nilotinib 300 mg twice daily: 14.8% of patients
- Bosutinib 500 mg daily: 10.8% of patients
Second-line therapy shows higher rates, ranging from 17.0% to 45.8% depending on the TKI and dose. 1
Timing and Management
- Peak incidence occurs within the first 4-6 weeks after starting TKI treatment 1
- Transient cytopenias are expected due to delayed recovery of normal hematopoiesis 1
- Management includes: treatment interruption (37% of patients), dose reduction, and filgrastim support (14% of patients with cytopenias) 2
- Blood counts should be monitored every 15 days until complete hematological response without significant cytopenias is achieved 1
Critical Distinction
The question likely confuses CML with other conditions. Neutropenia at presentation would be highly atypical for CML and should prompt consideration of alternative diagnoses or disease transformation to accelerated/blast phase. 1