Overview & Definition
Leukemia is a cancer of the early blood-forming cells in the bone marrow. It causes the uncontrolled production of abnormal white blood cells (blasts) that crowd out normal red cells, healthy white cells, and platelets, leading to severe anemia, neutropenic infection, and bleeding risk.
The Four Major Subtypes of Leukemia
- Acute Myeloid Leukemia (AML) – rapid proliferation of immature myeloid blasts requiring immediate induction chemotherapy.
- Acute Lymphoblastic Leukemia (ALL) – malignant transformation of immature B- or T-lymphoblasts, common in children and young adults.
- Chronic Myelogenous Leukemia (CML) – driven by the Philadelphia chromosome t(9;22) BCR-ABL1 fusion gene, highly responsive to oral TKIs.
- Chronic Lymphocytic Leukemia (CLL) – indolent accumulation of mature-appearing B lymphocytes, managed with targeted BTK or BCL-2 inhibitors.
Common Symptoms & Warning Signs
Diagnostic Evaluation
Precise subtype classification and molecular risk stratification are essential:
- 🔍 Peripheral Blood Smear & CBC – detecting circulate blast cells, cytopenias, or marked leukocytosis.
- 🔍 Bone Marrow Aspiration & Trephine Biopsy – quantifying bone marrow blast percentage (≥20% defining acute leukemia).
- 🔍 Flow Cytometry Immunophenotyping – determining lineage (B-cell, T-cell, Myeloid) and surface marker expression (CD19, CD33, CD34, CD117).
- 🔍 Cytogenetics (FISH & Karyotyping) & NGS Panels – identifying driver mutations (FLT3, NPM1, TP53, BCR-ABL1).
Treatment Options & Clinical Management
- 💊 Induction Chemotherapy (7+3 Protocol) – Cytarabine + Anthracycline for acute myeloid leukemia to achieve complete remission.
- 💊 Targeted Tyrosine Kinase Inhibitors (TKIs) – daily oral Imatinib, Dasatinib, or Nilotinib for CML.
- 💊 Targeted BTK & BCL-2 Inhibitors – Acalabrutinib, Zanubrutinib, or Venetoclax for CLL and relapsed AML.
- 💊 Intrathecal Chemotherapy & CNS Prophylaxis – preventing central nervous system relapse in ALL.
- 💊 Allogeneic Stem Cell Transplant – primary curative option for intermediate/high-risk AML and relapsed ALL.
- 💊 CAR-T Cell Therapy – for relapsed/refractory B-cell ALL.
Frequently Asked Questions
Acute leukemias (AML, ALL) progress rapidly with immature non-functional blast cells and require urgent hospital admission for induction therapy. Chronic leukemias (CML, CLL) progress more slowly over months or years, often allowing outpatient oral targeted pill management.
Many forms of leukemia, particularly childhood ALL, Acute Promyelocytic Leukemia (APL), and acute leukemias treated with Allogeneic Stem Cell Transplantation, can achieve permanent long-term cure. Chronic leukemias can be effectively controlled for decades with oral targeted therapies.