Leukemia

Leukemia is not one disease. It is a group of cancers arising in bone marrow and blood-forming cells. Major categories include acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), chronic myeloid leukemia (CML), and chronic lymphocytic leukemia (CLL).

These diseases differ greatly in age distribution, biology, treatment, and prognosis. A general leukemia page should function as an overview and link to subtype-specific pages rather than implying one universal treatment pathway.

• Fatigue, pallor, or shortness of breath from anemia
• Repeated infection or persistent fever
• Easy bruising, nosebleeds, gum bleeding, or petechiae
• Bone or joint pain
• Enlarged lymph nodes, liver, or spleen
• Night sweats or unexplained weight loss
• Central nervous system or testicular involvement in some ALL cases
• Breathing or neurologic symptoms with very high white blood cell counts
• Severe coagulopathy in acute promyelocytic leukemia (APL), which is a medical emergency

Chronic leukemia may be discovered on a routine blood count before symptoms appear.

• Age, with different patterns for each subtype
• Previous chemotherapy or radiation therapy
• High-dose ionizing radiation
• Occupational benzene exposure
• Smoking, particularly in relation to AML
• Down syndrome, Fanconi anemia, and other inherited syndromes
• Myelodysplastic syndromes or myeloproliferative neoplasms
• HTLV-1 infection in adult T-cell leukemia/lymphoma
• Inherited predisposition syndromes for myeloid or lymphoid malignancies

Most people with leukemia do not have one identifiable cause, and most people with a risk factor do not develop leukemia.

• There is no validated routine leukemia screening program for asymptomatic people at average risk.
• A complete blood count can reveal abnormalities but is not an established population screening test for leukemia.
• Avoiding tobacco, benzene, and unnecessary radiation has general preventive value.
• People with inherited predisposition or prior leukemogenic therapy may need specialist surveillance.
• Supplements, detox programs, and specific diets should not be promoted as proven leukemia prevention.

Diagnosis is discussed within the Overview, Screening, Staging, and Biomarkers sections above for this cancer type. Specific tests depend on presentation, site, and pathology.

Leukemia generally does not use solid-tumor TNM staging.

AML and ALL are classified and risk-stratified by WHO/International Consensus categories, cytogenetics, molecular findings, age, white blood cell count, treatment response, and measurable residual disease.

CML is described by chronic, accelerated, and blast phases, although classification criteria can evolve.

CLL commonly uses Rai or Binet staging and integrates TP53, IGHV, and other prognostic markers.

Remission does not necessarily mean that relapse is impossible. Measurable residual disease can detect leukemia below the sensitivity of routine microscopy.

Leukemia arises when a hematopoietic stem or progenitor cell acquires clonal genetic and epigenetic changes.

Acute leukemia is characterized by arrested differentiation and rapid accumulation of immature cells. Chronic leukemia cells are often more mature but accumulate abnormally.

Fusion genes, kinase activation, altered transcription, DNA methylation, impaired apoptosis, and clonal evolution are central mechanisms. Treatment can eliminate the dominant clone while smaller resistant clones survive and later expand.

• AML: NPM1, FLT3, IDH1, IDH2, CEBPA, TP53, RUNX1, KMT2A rearrangements, and core-binding-factor fusions
• APL: PML::RARA
• B-ALL: BCR::ABL1, KMT2A rearrangements, ETV6::RUNX1, hyperdiploidy, Philadelphia-like features, CD19, and CD22
• T-ALL: T-cell immunophenotype and multiple signaling alterations
• CML: BCR::ABL1, monitored with quantitative PCR
• CLL: TP53 mutation or deletion 17p, IGHV mutation status, and complex karyotype
• Measurable residual disease by flow cytometry, PCR, or high-throughput sequencing

The method and clinical threshold for measurable residual disease differ by leukemia subtype and treatment protocol.

• AML: intensive induction and consolidation for eligible patients; lower-intensity regimens for many older or medically frail patients; targeted therapy for FLT3, IDH, NPM1/KMT2A, and other selected alterations; allogeneic stem-cell transplantation for selected risk groups.
• APL: all-trans retinoic acid and arsenic trioxide are central treatments, with urgent management of coagulopathy.
• ALL: multi-phase therapy with induction, consolidation, and maintenance; selected use of antibodies, bispecific antibodies, tyrosine kinase inhibitors, CAR T-cell therapy, and transplantation.
• CML: BCR::ABL1 tyrosine kinase inhibitors with scheduled molecular monitoring.
• CLL: many asymptomatic early-stage patients are observed; when treatment is needed, BTK inhibitors, BCL-2 inhibitors, and anti-CD20 antibodies are commonly used in continuous or fixed-duration strategies.
• Treatment must be designed by a hematologic oncology team for the exact subtype.

• AML: cytarabine, daunorubicin or idarubicin, venetoclax, azacitidine, decitabine, FLT3 inhibitors, IDH1/2 inhibitors, gemtuzumab ozogamicin, and menin inhibitors
• APL: all-trans retinoic acid and arsenic trioxide, with additional agents in selected risk groups
• ALL: vincristine, corticosteroids, anthracyclines, asparaginase, methotrexate, mercaptopurine, blinatumomab, inotuzumab ozogamicin, tyrosine kinase inhibitors, and CAR T-cell products
• CML: imatinib, dasatinib, nilotinib, bosutinib, ponatinib, asciminib, and other approved TKIs
• CLL: ibrutinib, acalabrutinib, zanubrutinib, venetoclax, obinutuzumab, rituximab, pirtobrutinib, and other subtype-appropriate agents

• Bone marrow suppression causing infection, anemia, and bleeding
• Tumor lysis syndrome
• Need for blood or platelet transfusion
• Drug-specific cardiac, hepatic, pancreatic, neurologic, or vascular toxicity
• APL differentiation syndrome and coagulopathy
• Graft-versus-host disease after allogeneic transplantation
• Cytokine release syndrome and neurotoxicity with CAR T-cell therapy or bispecific antibodies
• Supportive care may include antimicrobial prevention or treatment, transfusion, tumor lysis prevention, fertility preservation, nutrition, oral care, and psychosocial support.

Fever during leukemia treatment usually requires immediate contact with the hematology team because infection can become life-threatening quickly.

• Menin inhibitors are an important new strategy for KMT2A-rearranged and NPM1-mutated acute leukemias.
• Highly sensitive measurable residual disease testing is being used to refine treatment intensity and transplant decisions.
• Blinatumomab and other immune therapies are moving into earlier phases of ALL treatment.
• New CAR T-cell, bispecific antibody, and off-the-shelf cellular approaches are being developed.
• Fixed-duration combinations of BTK and BCL-2 inhibitors are being studied in CLL.
• Single-cell analysis and clonal evolution studies aim to predict resistance before overt relapse.
• Recent U.S. regulatory examples include FDA approval of revumenib for relapsed or refractory NPM1-mutated AML on October 24, 2025, and approval on May 13, 2026, of oral decitabine/cedazuridine with venetoclax for newly diagnosed AML in adults age 75 or older or with comorbidities that preclude intensive induction.

• What is the complete leukemia subtype and WHO/International Consensus classification?
• Which chromosome changes, fusion genes, and mutations are present?
• What is my risk group, and how was it determined?
• What is the goal of each treatment phase?
• How and when will measurable residual disease be tested?
• Might I need an allogeneic stem-cell transplant?
• Should I be evaluated for an inherited blood-cancer predisposition?
• How will infection, bleeding, and tumor lysis be prevented?
• Which symptoms require immediate hospital assessment?
• Are targeted therapy, immunotherapy, or a clinical trial appropriate?