Leukemia: Types, Symptoms, Diagnosis, and Treatment Overview
What Is Leukemia?
Leukemia is a malignant clonal proliferation of hematopoietic stem/progenitor cells in the bone marrow, leading to accumulation of abnormal white blood cells that crowd out normal hematopoiesis.
Major Types (WHO Classification)
| Type | Cell of Origin | Typical Age | Acute vs. Chronic |
|---|
| Acute Lymphoblastic Leukemia (ALL) | Lymphoid precursor | Children (peak 2–5 yr) | Acute |
| Acute Myeloid Leukemia (AML) | Myeloid precursor | Adults (median 68 yr) | Acute |
| Chronic Lymphocytic Leukemia (CLL) | Mature B-cell | Older adults (median 70 yr) | Chronic |
| Chronic Myeloid Leukemia (CML) | Myeloid stem cell (BCR-ABL1) | Adults (median 65 yr) | Chronic |
Common Symptoms
- Fatigue, pallor (anemia)
- Recurrent infections (neutropenia)
- Easy bruising/bleeding (thrombocytopenia)
- Fever, night sweats, weight loss
- Lymphadenopathy, splenomegaly (especially CLL, CML)
- Bone pain (ALL in children)
Diagnosis
- CBC with differential + peripheral smear
- Bone marrow aspiration/biopsy (morphology, flow cytometry, cytogenetics, molecular)
- Immunophenotyping, FISH, PCR for fusion genes (e.g., BCR-ABL1, RUNX1-RUNX1T1)
Treatment by Type
- ALL: Multi-agent chemo (induction, consolidation, maintenance) ± targeted (TKI for Ph+), CAR-T, allo-HSCT for high-risk/relapse.
- AML: "7+3" induction (cytarabine + anthracycline) ± midostaurin/venetoclax/FLT3 inhibitors; consolidation chemo or allo-HSCT.
- CLL: Watch-and-wait for asymptomatic; BTK inhibitors (ibrutinib, acalabrutinib), BCL2 inhibitor (venetoclax), anti-CD20 antibodies.
- CML: TKIs (imatinib, dasatinib, nilotinib, bosutinib, ponatinib) – chronic daily oral therapy; monitor BCR-ABL1 PCR.
Prognosis
Varies widely by subtype, age, cytogenetics, molecular response, and fitness. Pediatric ALL cure rates >90%; AML in older adults remains challenging. CML has near-normal life expectancy on TKIs. Clinical trials offer access to novel therapies.
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