Acute myelogenous leukemia (AML) is a fast-growing cancer of the blood and bone marrow. In AML, the bone marrow makes many unformed cells called blasts. Blasts normally develop into white blood cells that fight infection. However, the blasts are abnormal in AML. They do not develop and cannot fight infections. The bone marrow may also make abnormal red blood cells and platelets. The number of abnormal cells (or leukemia cells) grows quickly. They crowd out the normal red blood cells, white blood cells and platelets the body needs.
Acute myelogenous leukemia symptoms and diagnosis
AML is the most common type of acute leukemia. More than 11,900 new cases occur in the United States each year, mostly in older adults. The average age of a person with AML is 65 years. Fewer than 10% of people with AML are children. Acute myelogenous leukemia is also called acute myeloblastic leukemia, acute myeloid leukemia, acute granulocytic leukemia or acute nonlymphocytic leukemia.
The symptoms of AML are caused by low numbers of healthy blood cells and high numbers of leukemia cells.
- White blood cells fight infection. Low numbers can lead to fever and frequent infections.
- Red blood cells carry oxygen throughout the body. Low numbers can lead to anemia — feeling tired or weak, being short of breath and looking pale.
- Platelets control bleeding. Low numbers can lead to easy bleeding or bruising and tiny red spots under the skin (petechiae).
- High numbers of leukemia cells may cause pain in the bones or joints.
A person with AML may feel generally unwell and run-down. He or she may also have other, less common symptoms.
AML is diagnosed when blood and bone marrow samples show a large number of leukemia cells. AML has eight subtypes, labeled M0 through M7. The subtypes are based on the type of blood cells affected. To find out the sub type and how well the leukemia might respond to treatment, the samples are looked at to find:
- The number of healthy blood cells.
- The size and number of leukemia cells.
- The changes that appear in the chromosomes of the leukemia cells. This is called cytogenetics.
- Other genetic abnormalities, e.g., FLT3 mutation, N-RAS.
Doctors also examine the patient to find out if leukemia cells have spread outside the blood and bone marrow. Doctors may use a chest X-ray and an ultrasound of the abdomen to look at the organs and tissues inside. They may also use a test called a lumbar puncture (spinal tap) to find out whether there are leukemia cells in the fluid around the brain and spinal cord.
Treatment options for acute myelogenous leukemia
AML can get worse quickly, so doctors usually begin treatment right away. To plan treatment, doctors look at a patient's risk factors (also called prognostic factors). Risk factors are patient and disease traits that clinical studies have linked to better or worse outcomes from treatment. Examples of risk factors are a patient's age and subtype of AML. To learn more about AML risk factors as well as how treatment options may differ for children or for adults older than age 60, see Risk Factors for Planning Treatment of AML.
For a patient with AML, the treatment plan may include:
- Chemotherapy — drugs that destroy cancer cells or stop them from growing (described below).
- A bone marrow or cord blood transplant (described below).
- All-trans retinoic acid (ATRA) if he or she has the subtype of AML known as promyelocytic leukemia.
- Other newer treatments that were recently developed or are still being studied in clinical trials — you can ask your doctor whether any newer treatments may be options for you.
Whichever treatment you and your doctor choose, you may be asked to be part of a clinical trial. Even standard treatments continue to be studied in clinical trials. These studies help doctors learn more about which treatments work best for which patients.
Chemotherapy for AML
For most patients, the standard first phase of AML treatment is induction chemotherapy. The goal of induction chemotherapy is to bring the disease into remission. Remission is when the patient's blood counts return to normal and bone marrow samples show no sign of disease (less than 5% of cells are leukemia cells).
Induction chemotherapy is very intense. It usually lasts one week, followed by three or more weeks for the patient to recover from the treatment. Often two drugs are used:
- Cytarabine (ara-C)
- An anthracycline drug such as daunorubicin (Daunomycin) or idarubicin (Idamycin)
Some patients may also be given additional drugs or different drugs. Patients who have the AML subtype promyelocytic leukemia also are given all-trans retinoic acid (ATRA).
If one week of treatment does not bring a remission, treatment may be repeated once or twice. Induction brings a complete remission in:
- About 70% to 80% of adults under age 60.
- About 50% of adults over age 60.
- More than 90% of children.
Successful induction chemotherapy destroys most of the leukemia cells, but a few will be left in the body. If these cells are not destroyed, they can cause a relapse of the disease. More treatment is needed to destroy the remaining leukemia cells. The next step may be consolidation chemotherapy or a transplant, depending on the treatment plan.
The second phase of chemotherapy is often called consolidation chemotherapy. The goal of consolidation chemotherapy is to destroy any remaining leukemia cells. A common treatment is high doses of cytarabine (ara-C) given in three or more cycles. Doctors may also use different drugs and schedules.
Consolidation chemotherapy is used to treat many patients with AML. It is the standard treatment at first remission for adults with low-risk cytogenetic factors (changes in the chromosomes of leukemia cells), especially adults younger than age 60.
Bone marrow or cord blood transplant for AML
For some patients, a bone marrow or cord blood transplant may offer the best chance for a long-term remission. A transplant is a strong treatment with risks of serious side effects, so it is not used for all patients with AML. A transplant is used when chemotherapy alone is unlikely to provide a long-term remission.
An autologous transplant uses blood-forming cells collected from the patient. If an autologous transplant is a treatment option for you, you will have blood-forming cells collected from your blood stream. The cells are usually collected after one or two cycles of consolidation treatment. The cells are frozen until you are ready for transplant. You may receive an autologous transplant soon after your induction therapy is completed, or your cells may be saved as a backup option in case you relapse after receiving consolidation chemotherapy.
Autologous transplants have risks of serious side effects, but these risks are lower than for allogeneic transplants. However, a patient has higher risks of a leukemia relapse after an autologous transplant. This is because leukemia cells may be returned to the patient along with his or her blood-forming cells.
An allogeneic transplant replaces the abnormal cells in a patient's bone marrow with healthy blood-forming cells from a family member or unrelated donor or cord blood unit. An allogeneic transplant has a higher risk of serious side effects than consolidation chemotherapy or an autologous transplant. However, the risk of relapse is lower after an allogeneic transplant.
Choosing a donor or cord blood unit
If an allogeneic transplant may be an option for you, your doctor will do a test to find out your HLA tissue type. Your doctor will also test possible donors in your family to find out if they are a suitable match for you.
In adults in good health with standard AML and a matched sibling, an allogeneic transplant may be considered after remission with induction therapy.
If you do not have a suitable donor in your family, your doctor can work with the National Marrow Donor Program® to search for an unrelated donor or cord blood unit for you from our Be The Match Registry® and other registries around the world. To save time, your doctor may check for potential donors on the registry at the same time he or she is testing for donors in your family.
The closeness of the donor match can affect a patient's chances of a good transplant outcome. In general, transplants using matched sibling donors have had the best results. However, outcomes for unrelated donor transplants have improved in the last decade. For some groups of patients, outcomes for sibling donor and unrelated donor transplants are similar.
Reduced-intensity and non-myeloablative transplants
For some people with AML, an allogeneic transplant may offer the best chance for a long-term remission. However, more than half of people with AML are over age 60. Many people older than age 60 are unable to tolerate the intense treatment of a standard transplant. People with other health problems, such as heart disease or organ damage from previous chemotherapy, may also be unable to tolerate a standard transplant. An allogeneic transplant using less intense treatment may be an option for some of these patients. This type of transplant is called a reduced-intensity transplant or non-myeloablative transplant.
Transplant success rates
Transplants have risks of serious complications, but a transplant offers some patients the best chance for a long-term remission. If transplant is an option for you, your doctor can talk with you about the possible risks and benefits of a transplant. For statistics showing patients' results after transplant, see AML Transplant Outcomes.
Making treatment decisions
AML is an acute disease that can get worse quickly. Most patients begin treatment with induction chemotherapy soon after diagnosis. Many patients reach remission, but relapse of AML is common. All patients need a second phase of treatment to try to prevent relapse. The second phase of treatment is based on a patient's risk factors. (For more information, see Risk Factors for Planning Treatment of AML.) It is important to discuss your risk factors and your treatment options with a doctor who is experienced in treating AML.
Planning for a possible transplant
All patients with AML may want to talk with their doctors about including the possibility of a transplant in their treatment plan. A transplant may be the first choice or it may be a backup plan. When transplant is not the first treatment, early planning may allow for more flexibility in treatment options and a quicker transplant later, if it is needed. In general, to prepare for the possibility of transplant:
- Patients with AML should be HLA tissue typed at diagnosis.
- Patients should be referred to a transplant doctor for consultation at an appropriate time based on risk factors.
- Family members who might be suitable donors should be tested at the same time as the patient or soon after.
- Doctors can take an early look at potential unrelated donors and cord blood units on the Be The Match Registry as soon as they know the patient's HLA tissue type. This first look is free of charge.
- Patients who have no suitable related donor and few potential unrelated donors may want to discuss storing their own blood-forming cells for a possible autologous transplant.
The only patients who may not benefit from this planning are those who would clearly be unable to tolerate even a reduced-intensity transplant. Some older patients and patients who have organ damage or other health problems may be unable to tolerate a transplant. If you want to consider a transplant, a transplant doctor can examine you to see whether a transplant is a good option.
It is important to talk about your treatment options with a doctor who is experienced in treating AML. Your doctor can discuss your specific risk factors and treatment options with you. For more information to help you talk to your doctor about whether a transplant is an option for you, you can share the referral guidelines (PDF) from the Physician Resources section of this Web site with your doctor.
More information on AML
You can get further information about AML from disease-specific organizations, such as:
For other organizations that offer information and resources, see Organizations That Can Help: A Searchable Directory.
C. F. LeMaistre, M.D., Southwest Texas Methodist Hospital, San Antonio, Texas
Paul Shaughnessy, M.D., Texas Transplant Institute, San Antonio, Texas
Anthony S. Stein, M.D., City of Hope National Medical Center, Duarte, Calif.