Acute myeloid leukemia (AML) is a type of white blood cell cancer. White blood cells serve to help your body fight infection. Your blood cells are formed in the bone marrow. However, in leukemia, the bone marrow produces abnormal white blood cells. These cells expel healthy blood cells, making it difficult for the blood to do its job. In acute myeloid leukemia (AML), there are too many myeloblasts, which is a type of white blood cell.
AML is the most common type of acute leukemia to occur in adults. This disease can get worse quickly if left untreated. Possible risk factors include smoking habits, previous chemotherapy treatment, and exposure to radiation.
Symptoms of AML include:
- Shortness of breath
- Easy bruising or bleeding
- Bleeding under the skin
- Weight loss or loss of appetite
To diagnose acute myeloid leukemia, a blood and bone marrow test is performed. Treatment includes chemotherapy, other drugs, radiation therapy, stem cell transplant, and targeted therapy. Targeted therapy uses substances that attack cancer cells without damaging normal cells. Once the leukemia goes into remission, you will need additional treatment to ensure that the leukemia does not recur.
General Overview of Adult Acute Myeloid Leukemia
- Acute myeloid leukemia (AML) in adults is a type of cancer in which the bone marrow produces abnormal myeloblasts (a type of white blood cell), red blood cells, or platelets.
- Leukemia can affect red blood cells, white blood cells, and platelets.
- There are different subtypes of the AML.
- Smoking habits, previous chemotherapy treatments, and radiation exposure can may trigger AML in adults
- Signs and symptoms of adult AML include fever, feeling tired, and easy bruising or bleeding.
- Tests that examine the blood and bone marrow are used to detect and diagnose adult AML.
- Certain factors influence prognosis (chance of recovery) and treatment options.
Adult acute myeloid leukemia (AML) is a type of cancer in which the bone marrow makes abnormal myeloblasts (a type of white blood cell), red blood cells, or platelets.
Adult acute myeloid leukemia (AML) is a cancer of the blood and bone marrow. This type of cancer usually gets worse quickly if left untreated. It is the most common type of acute leukemia in adults. AML is also called acute myelogenous leukemia, acute myeloblastic leukemia, acute granulocytic leukemia, and acute non-lymphocytic leukemia.
The bone consists of compact bone, spongy bone, and bone marrow. Compact bone forms the outer layer of bone. Spongy bones are located at the ends of the bones and contain red bone marrow. Bone marrow is usually found in the centre of most bones and has many blood vessels. There are two types of bone marrow: red and yellow. Red bone marrow contains blood stem cells that can turn into red blood cells, white blood cells, or platelets. Meanwhile, yellow bone marrow is mostly made of fat.
Leukemia can affect red blood cells, white blood cells, and platelets.
Normally, the bone marrow makes blood stem cells (immature cells) that become mature blood cells over time. Blood stem cells can become myeloid stem cells or lymphoid stem cells. Lymphoid stem cells become white blood cells.
Myeloid stem cells form one of three types of mature blood cells:
- Red blood cells that carry oxygen and other substances to all body tissues.
- Platelets that form blood clots to stop bleeding.
- Granulocytes (white blood cells) that fight infection and disease.
Blood stem cells go through several steps to become red blood cells, platelets, or white blood cells.
In AML, myeloid stem cells usually become a type of immature white blood cell called myeloblast (or myeloid blast). The myeloblasts in AML are abnormal and do not become healthy white blood cells. Sometimes in AML, too many stem cells become abnormal red blood cells or platelets. The abnormal white blood cells, red blood cells, or platelets are also called leukemia cells or blasts. Leukemia cells can build up in the bone marrow and blood, so there is less room for healthy white blood cells, red blood cells, and platelets. When this happens, infection, anemia, or bleeding may easily occur. The leukemia cells can spread outside the blood to other parts of the body, including the central nervous system (brain and spinal cord), skin, and gums.
There are different subtypes of the AML.
Most subtypes of AML are based on how mature (developed) cancer cells are at the time of diagnosis and how different they are from normal cells.
Acute promyelocytic leukemia (APL) is a subtype of AML that occurs when parts of two genes stick together. LPA usually occurs in middle-aged adults. Signs of APL may include bleeding and blood clots.
Smoking, previous chemotherapy treatments, and exposure to radiation may affect the risk of adult AML
Anything that increases your risk of developing a disease is called a risk factor. Having a risk factor doesn’t mean you will get cancer; not having risk factors doesn’t mean you won’t get cancer. Consult your doctor if you think you might be at risk. Possible risk factors for AML include the following:
- Smoking, especially after the age of 60.
- Have had treatment with chemotherapy or radiation therapy in the past.
- Have had treatment for acute lymphoblastic leukemia as a child in the past.
- Exposure to radiation from an atomic bomb or chemical benzene
- Have a history of blood disorders such as myelodysplastic syndrome
Signs and symptoms of adult AML include fever, feeling tired, and easy bruising or bleeding.
The initial signs and symptoms of AML may be like those caused by the flu or other common illnesses. Check with your doctor if you have any of the following:
- Shortness of breath.
- Easy bruising or bleeding
- Petechiae (flat spots under the skin caused by bleeding).
- Weakness or feeling tired.
- Weight loss or loss of appetite.
Tests that examine the blood and bone marrow are used to detect and diagnose adult AML.
The following tests and procedures may be used:
- Physical test and medical history: An exam of the body to check for general signs of health, including checking for signs of disease, such as lumps or anything else that looks unusual. A history of the patient’s health habits and previous illnesses and treatments will also be conducted
- Complete blood count (CBC): A procedure in which a blood sample is drawn and checked for the following:
Blood is drawn by inserting a needle into a vein and allowing blood to flow into the tube. The blood sample is sent to the laboratory and red blood cells, white blood cells, and platelets are counted. HDL is used to test, diagnose and monitor a variety of conditions.
- The number of red blood cells, white blood cells, and platelets.
- The amount of hemoglobin (a protein that carries oxygen) in red blood cells.
- The portion of the sample consisting of red blood cells.
- Peripheral blood smear: A procedure in which a blood sample is checked for blast cells, white blood cell count and type, platelet count, and changes in blood cell shape.
- Bone marrow aspiration and biopsy: The removal of bone marrow, blood, and a small piece of bone by inserting a hollow needle into the hip or sternum. A pathologist looks at the bone marrow, blood, and bone under a microscope for signs of cancer.
After a small area of skin is numbed, a bone marrow needle is inserted into the patient’s hip bone. The samples of blood, bone, and bone marrow are removed to be viewed under a microscope
- Cytogenetic analysis: A laboratory test in which cells in a sample of blood or bone marrow sample are viewed under a microscope for specific changes in chromosomes. Other tests, such as fluorescence in situ hybridization (FISH), may also be performed to look for certain changes in chromosomes.
- Immunophenotyping: A process used to identify cells, based on the type of antigen or markers on the cells’ surface. This process is used to diagnose subtypes of AML by comparing cancer cells with normal cells of the immune system. For example, cytochemical research can test cells in a tissue sample using chemicals (dyes) to look for certain changes in the sample. A chemical can cause a discoloration in one type of leukemia cell but not in another type of leukemia cell.
- Reverse transcription – polymerase chain reaction (RT-PCR): A laboratory test where cells in a tissue sample are examined using chemicals to look for certain changes in the gene’s structure or function. This test is used to diagnose certain types of AML including acute promyelocytic leukemia (APL).
Certain factors influence prognosis (chance of recovery) and treatment options.
Prognosis (chance of recovery) and treatment options depend on:
- Patient’s age.
- AML subtypes.
- Whether the patient received chemotherapy in the past to treat a different cancer.
- Whether there is a history of blood disorders such as myelodysplastic syndrome.
- Whether the cancer has spread to the central nervous system.
- Whether the cancer has been treated previously or recurred (come back).
It is important that acute leukemia be treated immediately.
Stages of Adult Acute Myeloid Leukemia
- Once adult acute myeloid leukemia (AML) has been diagnosed, tests are done to find out if the cancer has spread to other parts of the body.
- There is no standard staging system for adult AML.
Once adult acute myeloid leukemia (AML) has been diagnosed, tests are done to find out if the cancer has spread to other parts of the body.
The extent or spread of cancer is usually described as stages. In adult acute myeloid leukemia (AML), the subtype of AML and whether the leukemia has spread outside the blood and bone marrow is used instead of the stage for planning treatment. The following tests and procedures can be used to determine if the leukemia has spread:
- Lumbar puncture: A procedure used to collect cerebrospinal fluid (CSF) samples from the spinal column. This is done by placing a needle between two bones in the spine and into the CSS around the spinal cord and removing a sample of the fluid. The CSF sample is examined under a microscope for signs that the leukemia cells have spread to the brain and spinal cord. This procedure is also called an LP or spinal tap.
The patient lies in a curled position on a table. After a small area in the lower back is numbed, a spinal needle (long and thin needle) is inserted into the lower part of the spine to remove cerebrospinal fluid (CSF). The fluid may be sent to a laboratory for testing.
- CT scan (CAT scan): A procedure that makes a series of detailed images of the abdomen, taken from multiple angles. The images are created by a computer connected to an x-ray machine. A dye may be injected into a vein or swallowed to help an organ or tissue appear more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
There is no standard staging system for adult AML
The disease is described as untreated, in remission, or recurrent.
Untreated adult AML
In untreated adult AML, the disease is newly diagnosed. It has not been treated except to relieve signs and symptoms such as fever, bleeding, or pain, and the following are true:
- There is abnormal complete blood count.
- At least 20% of the cells in the bone marrow are blasts (leukemia cells).
- There are signs or symptoms of leukemia.
Adult AML in remission
In adult AML in remission, the disease has been treated and the following are true:
- There is normal complete blood count.
- Less than 5% of the cells in the bone marrow are blasts (leukemia cells).
- There are no signs or symptoms of leukemia in the brain and spinal cord or elsewhere in the body.
Recurrent Adult AML
Recurrent adult AML is cancer that has recurred (comes back) after it has been treated. The AML may return in the blood or bone marrow.
Overview of Treatment Options
- There are different types of treatment for patients with adult acute myeloid leukemia.
- Treatment for adult AML usually has 2 phases.
- Four types of standard treatment are used:
- Radiation therapy
- Stem cell transplant
- Other drug therapy
- New types of treatment are being tested in clinical trials.
- Targeted therapy
- Patients may consider taking part in clinical trials.
- Patients can enter clinical trials before, during, or after starting their cancer treatment.
- Follow-up tests may be required.
There are different types of treatment for patients with adult acute myeloid leukemia.
Various types of treatments are available to treat adult acute myeloid leukemia (AML). Some are standard treatments (currently used treatment), and some are being tested in clinical trials. A clinical trial is research intended to help improve current treatments or obtain information onnew treatments for cancer patients. When clinical trials show that the new treatment is better than standard treatment, the new treatment can become standard treatment. Certain clinical trials are only open to patients who have not started treatment.
Treatment for adult AML usually has 2 phases.
The two phases of adult AML are:
- Remission induction therapy: This is the first phase of treatment. The goal is to kill leukemia cells in the blood and bone marrow. This puts the leukemia into remission.
- Post-remission therapy: This is the second phase of treatment. It begins after the leukemia is in remission. The goal of post-remission therapy is to kill any remaining leukemia cells that may be inactive but could begin to regrow and cause a relapse. This phase is also called remission continuation therapy.
Four types of standard treatment are used:
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. The chemotherapy is either taken by mouth or injected into a vein or muscle, with the drugs entering the bloodstream and reaching cancer cells throughout the body (systemic chemotherapy). Chemotherapy can also be placed directly into the cerebrospinal fluid (intrathecal chemotherapy), organs, or body cavities (e.g. the stomach), or affect cancer cells in the areas concerned (regional chemotherapy). Intrathecal chemotherapy may be used to treat adult AML that has spread to the brain and spinal cord. Combination chemotherapy is treatment using more than one anticancer drug.
The way the chemotherapy is given depends on the subtype of AML being treated and whether leukemia cells have spread to the brain and spinal cord.
Radiation therapy is a cancer treatment that uses high-energy X-rays or other types of radiation to kill cancer cells or prevent them from growing. There are two types of radiation therapy:
- External radiation therapy uses a machine outside the body to send radiation towards the cancer.
- Internal radiation therapy uses radioactive substances placed in needles, beads, cables, or catheters that are placed directly into or near the cancer.
The way radiation therapy is given depends on the type of cancer being treated and whether the leukemia cells have spread to the brain and spinal cord. External radiation therapy is used to treat adult AML.
Stem cell transplant
Stem cell transplant is a method of giving chemotherapy and replacing blood-forming cells. Stem cells (immature blood cells) are removed from the patient or donor’s blood or bone marrow and are frozen and stored. After the patient completes chemotherapy, the stored stem cells are thawed and given back to the patient through an IV. These reinfused stem cells grow into (and restore) the body’s blood cells.
Other drug therapies
Arsenic trioxide and all-trans retinoic acid (ATRA) are anticancer drugs that kill leukemia cells, stop leukemia cells from dividing, or help leukemia cells mature into white blood cells. These medications are used in the treatment of a subtype of AML called acute promyelocytic leukemia.
New types of treatment are being tested in clinical trials.
This summary section describes treatments that are being studied in clinical trials. This section may not mention every new treatment being studied.
Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells without damaging normal cells. Monoclonal antibody therapy is one type of targeted therapy being studied in the treatment of adult AML.
Monoclonal antibody therapy is a cancer treatment that uses antibodies made in the laboratory from a single type of immune system cell. These antibodies can identify substances in cancer cells or normal substances that can help cancer cells grow. The antibodies attach to these substances and kill the cancer cells, block their growth, or prevent them from spreading. Monoclonal antibodies are given by infusion. These antibodies may be used alone or to carry drugs, toxins, or radioactive material directly to cancer cells.
Patients may intend to take part in clinical trials.
For some patients, taking part in clinical trials may be the best treatment option. Clinical trials are part of the cancer research process. Clinical trials are conducted to find out whether new cancer treatments are safe and effective or better than standard treatments.
Many of today’s standard treatments for cancer are based on previous clinical trials. Patients who take part in clinical trials may receive standard treatment or be among the first to receive a new treatment.
Patients who take part in clinical trials are also helping to improve the way cancer will be treated in the future. Even when they do not produce new and effective treatments, clinical trials often answer important questions and help move research forward. .
Patients can enter clinical trials before, during, or after starting their cancer treatment.
Some clinical trials only include patients who have not received treatment. Other trial test treatments for patients whose cancer has not improved. There are also clinical trials that test new ways to stop cancer from recurring (coming back) or reduce the side effects of cancer treatment.
Follow-up tests may be required
Some of the tests that were done to diagnose cancer or to find out the stage of the cancer may be repeated. Several tests will be repeated to see how well the treatment is working. The decision about whether to continue, change, or stop treatment may be based on the results of these tests.
Some tests will continue to be done from time to time after treatment has completed. The results of these tests can show if your condition has changed or if the cancer has recurred (came back). These tests are sometimes called follow-up test or check-ups.
Treatment for Untreated Adult Acute Myeloid Leukemia
Untreated Acute Myeloid Leukemia in Adults
Standard treatment for untreated adult acute myeloid leukemia (AML) during the remission induction phase depends on the subtype of AML and may include the following:
- Combination chemotherapy.
- High-dose combination chemotherapy.
- Low-dose chemotherapy.
- Intrathecal chemotherapy.
- All-trans retinoic acid (ATRA) plus arsenic trioxide for the treatment of acute promyelocytic leukemia (APL).
- ATRA plus combination chemotherapy followed by arsenic trioxide for the treatment of APL
Adult Acute Myeloid Leukemia in Remission
Treatment of adult AML during the remission phase depends on the subtype of AML and may include the following:
- Combination chemotherapy.
- High-dose chemotherapy, with or without radiation therapy, and stem cell transplant using the patient’s stem cells.
- High-dose chemotherapy and stem cell transplant using donor stem cells.
- A clinical trial of arsenic trioxide
Recurrent Adult Acute Myeloid Leukemia
There is no standard treatment for recurrent adult AML. Treatment depends on the subtype of the AML and may include the following:
- Combination chemotherapy.
- Targeted therapy with monoclonal antibodies.
- Stem cell transplant.
- Arsenic trioxide therapy.
- A clinical trial of arsenic trioxide therapy was followed by stem cell transplant