Adult Acute Myeloid Leukemia (AML)

Most acute myeloid leukemia subtypes are determined by the cancer cells' maturity (development) and degree of divergence from normal cells at the time of diagnosis.

Acute promyelocytic leukemia (APL) is a kind of leukemia that originates when sections of two genes bind together. APL typically affects middle-aged adults. APL symptoms can include bleeding and the formation of blood clots.

Having or not having a risk factor does not guarantee that you will develop cancer. If you believe you are at risk, consult your doctor. The following are the possible risk factors for acute myeloid leukemia:

• Male sex
• Smoking, especially after 60 years
• Having had treatment with chemotherapy or radiation therapy in the past
• Having had treatment for childhood acute lymphoblastic leukemia (ALL) in the past
• Being exposed to radiation from an atomic bomb or the chemical benzene
• Having a history of a blood disorder, such as myelodysplastic syndrome

Early acute myeloid leukemia signs and symptoms could be like the flu or other common illnesses. Consult your doctor if you experience any of the following symptoms:

• Fever
• Shortness of breath
• Easy bruising or bleeding
• Petechiae (flat, pinpoint spots under the skin caused by bleeding)
• Weakness or feeling tired
• Weight loss or loss of appetite

The following tests and procedures may be used:

• Physical examination and medical history: To check for general health indicators, including looking for disease symptoms, such as tumors, or anything else that seems unusual. Additionally, a history of the person’s health, lifestyle, diseases, and treatments.
• Complete blood count: To check the number of platelets, white blood cells, and red blood cells; hemoglobin (the protein that transports oxygen) and the composition of red blood cells.
• Peripheral blood smear: Examines a sample of blood for blast cells, the quantity and types of white blood cells, the number of platelets, and changes in blood cell shape.
• Bone marrow aspiration and biopsy: A hollow needle is inserted into the hipbone or breastbone to extract a small amount of liquid bone marrow and a sample of tissue, which the pathologist examines under a microscope for indications of cancer.
• Cytogenetic analysis: A sample of bone marrow or blood is examined under a microscope to look for specific chromosomal alterations. Fluorescence in situ hybridization could be done to check for specific chromosomal abnormalities.
• Immunophenotyping: Determines the subtype of AML by comparing cancer cells to immune system cells. Cytochemistry research, for example, may test the cells in a tissue sample using chemicals (dyes) to look for specific alterations. In one type of leukemia cell, this chemical may alter its color.
• Reverse transcription-polymerase chain reaction test: Examines cells in a tissue sample using chemicals to look for specific alterations to the structure or function of genes. Acute promyelocytic leukemia is diagnosed using this test.

Adult acute myeloid leukemia is treated based on the subtype of the disease and whether it has progressed outside of the blood and bone marrow. To find out if leukemia has spread, the following tests and procedures could be used:

• Lumbar puncture: A sample of the cerebrospinal fluid (CSF) surrounding the spinal cord is taken by inserting a needle between two vertebrae in the spine and into the fluid. Under a microscope, the sample of CSF is examined for indications that leukemia cells have spread to the brain and spinal cord.
• CT scan: Creates a series of fine-grained images of the abdomen from various angles. A computer and an X-ray machine are connected to create the images.

There are some standard treatments (the treatment that is currently in use) and ongoing clinical studies for acute myeloid leukemia (AML). A clinical trial for treatment is a research project designed to find out more about potential new treatments for cancer or enhance existing treatments. A new treatment might replace the standard one if clinical trials reveal that it is superior to the current one. People who have not started on treatment can participate in some clinical trials.

Stages of treatment

The two stages of adult AML treatment are

1. Remission-inducing treatment: The first stage of treatment aims to destroy leukemia cells in the bone marrow and blood. As a result, the leukemia is in remission.
2. Post-remission treatment: The second stage of treatment starts once leukemia has gone into remission. Post-remission treatment aims to kill any leftover leukemia cells that may not be active but could develop and trigger a recurrence. This stage is also called remission continuation treatment.

The following standard treatments are used:

Chemotherapy

Uses medications to inhibit the growth of cancer cells by killing the cells or preventing them from dividing. Chemotherapy medications are administered orally, intravenously, or intramuscularly (systemic chemotherapy). Chemotherapy mostly affects cancer cells in such regions when administered intrathecally into the cerebrospinal fluid, an organ, or a body cavity, such as the abdomen (regional chemotherapy). Adult AML with spinal cord and brain metastases could be treated with intrathecal chemotherapy. Multiple anticancer medications are used during combination chemotherapy.

Depending on the AML subtype being treated and whether the brain and spinal cord have been affected by leukemia cells, different chemotherapy regimens are used.

Radiation therapy

High-energy radiation, such as X-rays or other forms of radiation, is used in radiation therapy to either kill or stop the growth of cancer cells. There are two types of radiation therapy:

1. External radiation therapy: A machine is used outside the body to direct radiation toward cancer.
2. Internal radiation therapy: Involves inserting catheters, seeds, wires, or needles into or close to cancer to administer radioactive substances.

The type of cancer being treated and whether leukemia cells have spread to the brain and spinal cord determine how radiation therapy is administered. The treatment for adult AML involves external radiation therapy.

Stem cell transplant

Chemotherapy can be administered through a stem cell transplant to replace blood-forming cells that have been damaged by cancer treatment. From the person’s or a donor's bone marrow or blood, stem cells (immature blood cells) are extracted, frozen, and stored. After the treatment is finished, the stored stem cells are thawed and administered to the person. These stem cells are reinfused and developed into (and restore) the body's blood cells.

Other drug treatment

Arsenic trioxide and all-trans retinoic acid kill leukemia cells, prevent them from proliferating or help them mature into white blood cells. These medications are used to treat acute promyelocytic leukemia.

Untreated adult acute myeloid leukemia

Depending on the subtype of acute myeloid leukemia (AML), the standard treatment during the remission induction phase may involve the following:

• Combination chemotherapy
• High-dose combination chemotherapy
• Low-dose chemotherapy
• Intrathecal chemotherapy
• All-trans retinoic acid (ATRA) and arsenic trioxide to treat acute promyelocytic leukemia (APL)
• ATRA and combination chemotherapy followed by arsenic trioxide for the treatment of APL

Acute myeloid leukemia in remission in adults

Depending on the subtype of AML, treatment for adult AML during the remission period could be the following:

• Combination chemotherapy
• High-dose chemotherapy (with or without radiation therapy) and stem cell transplant using the person’s stem cells
• High-dose chemotherapy and stem cell transplant using donor stem cells
• A clinical trial of arsenic trioxide

Adult recurrent acute myeloid leukemia

Recurrent adult AML does not have a standard treatment. Depending on the AML subtype, the following treatments might be used:

• Combination chemotherapy
• Targeted therapy with monoclonal antibodies
• Stem cell transplant
• Arsenic trioxide therapy
• A clinical trial of arsenic trioxide therapy followed by the stem cell transplant

The prognosis and treatment options are determined by

• Age at diagnosis
• The subtype of acute myeloid leukemia
• Whether the person received chemotherapy in the past to treat a different cancer
• Whether there is a history of a blood disorder, such as myelodysplastic syndrome
• Whether cancer has spread to the central nervous system
• Whether cancer has been treated before or recurred