Acute myeloid leukemia, commonly known as AML, is a rapidly progressing cancer of the blood and bone marrow. The disease begins in cells that normally develop into certain types of blood cells, particularly myeloid cells. As abnormal immature cells multiply, they can interfere with the production of healthy red blood cells, white blood cells, and platelets. AML can develop at almost any age but occurs more frequently in adults, particularly older adults. Because the disease can progress quickly, prompt medical evaluation is important when symptoms or abnormal blood-test results raise concern.
AML is a cancer that affects the blood-forming tissues of the body. It begins when immature myeloid cells acquire genetic changes that interfere with normal cell development and growth.
Under normal circumstances, bone marrow produces immature cells that gradually mature into functioning blood cells. In AML, abnormal immature cells called blasts accumulate in the bone marrow and blood.
These leukemia cells do not function like normal mature blood cells. Their increasing numbers can also crowd the bone marrow, leaving less room for healthy blood-cell production.
The resulting shortage of normal blood cells explains many of the symptoms associated with AML.
Healthy bone marrow maintains a balance between producing new blood cells and removing older cells. Genetic changes can disrupt this balance.
In AML, mutations or other chromosome changes can cause immature myeloid cells to remain in an abnormal state while continuing to multiply.
Different genetic abnormalities can produce different forms of AML. Molecular testing has therefore become an important part of diagnosis and treatment planning.
Some AML cases develop without a clearly identifiable cause. Other cases may occur after previous chemotherapy or radiation treatment for another cancer, or in association with certain blood disorders.
AML symptoms often develop over a relatively short period because the disease interferes with normal blood-cell production.
Common symptoms may include:
These symptoms are not specific to AML. Many other conditions can produce similar problems, which is why blood testing and medical evaluation are necessary for diagnosis.
Red blood cells carry oxygen throughout the body. When AML reduces the production of healthy red blood cells, anemia can develop.
Anemia may cause tiredness, weakness, dizziness, headaches, pale skin, and shortness of breath.
The severity of symptoms can depend on how quickly the red blood-cell count falls and how low the count becomes.
White blood cells play a major role in protecting the body from infections. AML can interfere with the production of normal white blood cells.
Although the total white blood-cell count may sometimes be high, many of the cells can be immature and unable to perform normal immune functions.
As a result, people with AML can have an increased risk of bacterial, viral, or fungal infections.
Fever during AML can be clinically significant, particularly when the number of functioning infection-fighting cells is low.
Platelets help control bleeding by forming clots at sites of blood-vessel injury.
AML can reduce platelet production by crowding the bone marrow with abnormal cells. Low platelet levels, known as thrombocytopenia, can lead to easy bruising, frequent nosebleeds, bleeding gums, heavier menstrual bleeding, or small pinpoint skin spots called petechiae.
Severe reductions in platelets can increase the risk of serious bleeding.
The exact cause of most AML cases is unknown.
AML develops because of genetic changes in blood-forming cells. These changes can occur spontaneously during a person's lifetime.
Several factors have been associated with an increased risk of AML.
Certain chemotherapy medicines and radiation therapy can increase the risk of developing AML years after treatment for another cancer.
AML that develops following previous cancer treatment is sometimes classified as therapy-related AML.
Certain disorders of the bone marrow can increase the risk of AML.
Examples include myelodysplastic syndromes and some myeloproliferative disorders.
High levels of ionizing radiation can increase the risk of leukemia.
The relationship depends on the level and circumstances of exposure.
AML can occur in younger adults and children, but the incidence increases substantially with age.
Older adults may also have other medical conditions that influence treatment decisions.
Certain inherited genetic conditions are associated with increased leukemia risk. However, most AML cases are not caused by inherited syndromes.
Diagnosis usually involves blood tests followed by examination of the bone marrow.
A complete blood count measures red blood cells, white blood cells, and platelets.
AML may produce abnormal levels of one or more blood-cell types. Immature blast cells may also appear in the bloodstream.
A blood test alone cannot establish every detail of AML, so additional laboratory testing is usually required.
A blood smear allows specialists to examine individual blood cells under a microscope.
The appearance and maturity of the cells can provide important clues about a possible leukemia.
Bone marrow examination is a central part of AML diagnosis.
During a bone marrow aspiration, a small amount of liquid marrow is collected. A biopsy may also be performed to examine the structure of the marrow.
Laboratory specialists evaluate the cells for abnormal features and determine the proportion of immature blasts.
Flow cytometry examines proteins expressed on the surface or inside of blood and bone marrow cells.
This testing can help identify the lineage and characteristics of leukemia cells.
Genetic testing helps identify chromosome abnormalities and mutations associated with AML.
Important genetic findings can influence classification, treatment selection, and prognosis.
Examples of genes commonly evaluated in AML include FLT3, NPM1, CEBPA, IDH1, and IDH2.
Not every person with AML has the same genetic abnormalities, which is one reason treatment plans differ from case to case.
AML is not a single uniform disease. It includes multiple subtypes and genetically defined categories.
Modern classification systems use chromosome changes, gene mutations, cell characteristics, and clinical history to distinguish different forms.
One particularly important subtype is acute promyelocytic leukemia, or APL.
APL is a distinct subtype of AML associated with a specific chromosome rearrangement involving the PML and RARA genes.
APL requires specialized treatment because it can cause serious bleeding and clotting complications.
Medicines such as all-trans retinoic acid and arsenic trioxide play major roles in the treatment of APL, with treatment approaches depending on disease risk and other clinical factors.
Because APL can deteriorate quickly, suspected cases require urgent specialist management.
AML treatment generally aims to eliminate leukemia cells, restore healthy blood-cell production, prevent complications, and reduce the risk of recurrence.
Treatment can involve chemotherapy, targeted therapy, stem cell transplantation, or combinations of these approaches.
The treatment strategy depends heavily on AML subtype and genetic findings.
For many patients, the first phase of treatment is called induction therapy.
The primary goal is to achieve remission by reducing leukemia cells to very low levels and restoring normal blood-cell production.
Traditional intensive induction chemotherapy has historically involved combinations of medicines such as cytarabine and an anthracycline.
However, treatment approaches have expanded considerably, and not every patient receives the same induction regimen.
Age, overall health, genetic findings, AML subtype, and other medical factors influence the treatment plan.
Achieving remission does not necessarily mean every leukemia cell has been eliminated.
Consolidation therapy is used after remission to reduce the risk of the leukemia returning.
Depending on the AML subtype and risk classification, consolidation may involve additional chemotherapy, targeted treatment, or stem cell transplantation.
Some AML cells contain specific genetic mutations that can be targeted with medicines designed to interfere with abnormal molecular pathways.
For example, FLT3 inhibitors may be used for AML with certain FLT3 mutations.
IDH inhibitors can be used in selected cases involving IDH1 or IDH2 mutations.
Other targeted medicines may be considered depending on the molecular characteristics of the leukemia.
These treatments illustrate why molecular testing is increasingly important in AML care.
Not every patient is able to tolerate intensive chemotherapy.
For older adults or individuals with significant health problems, lower-intensity treatment may be considered.
Combination approaches involving hypomethylating agents and targeted medicines such as venetoclax have become important in the management of many patients who are not candidates for intensive induction.
The goal remains effective disease control while considering treatment-related risks and overall health.
Allogeneic stem cell transplantation may be considered for certain patients with AML who have a substantial risk of relapse or who have disease that returns after initial treatment.
The procedure involves replacing diseased blood-forming cells with healthy stem cells from a suitable donor.
Before transplantation, treatment is used to reduce the leukemia burden and prepare the body for the donor cells.
Stem cell transplantation can provide a long-term remission and may be potentially curative in selected patients, but it also carries significant risks, including infections, organ complications, graft-versus-host disease, and treatment-related mortality.
The decision requires careful assessment of potential benefits and risks.