Treatment of most cases of acute myeloid leukemia (AML) is usually divided into 2 chemotherapy (chemo) phases:
- Remission induction (often just called induction)
- Consolidation (post-remission therapy)
Treatment usually needs to start as quickly as possible after the diagnosis because AML can progress very quickly. Sometimes another type of treatment needs to be started even before the chemo has had a chance to work.
Some people with AML have very high numbers of leukemia cells in their blood when they are diagnosed, which can cause problems with normal circulation. This is called leukostasis and was discussed in “Signs and symptoms of acute myeloid leukemia.” Chemo can take a few days to lower the number of leukemia cells in the blood. In the meantime, leukapheresis (sometimes just called pheresis) might be used before chemo.
For this procedure, the patient’s blood is passed through a special machine that removes white blood cells (including leukemia cells) and returns the rest of the blood to the patient. Two intravenous (IV) lines are required – the blood is removed through one IV, goes through the machine, and then is returned to the patient through the other IV. Sometimes, a single large catheter is placed in a vein in the neck or under the collar bone for the pheresis – instead of using IV lines in both arms. This type of catheter is called a central line and has both IVs built in.
This treatment lowers blood counts right away. The effect is only for a short time, but it may help until the chemo has a chance to work.
This first part of treatment is aimed at getting rid of as many leukemia cells as possible. How intense the treatment is can depend on a person’s age and health. Doctors often give the most intensive chemo to people under the age of 60. Some older patients in good health may benefit from similar or slightly less intensive treatment.
People who are much older or are in poor health might not do well with intensive chemo. Treatment of these patients is discussed below in “Treating frail, older adults.”
Age, health, and other factors clearly need to be taken into account when considering treatment options. Doctors are also trying to determine whether people with certain gene or chromosome changes are more likely to benefit from more intensive treatment.
In younger patients, such as those under 60, induction often involves treatment with 2 chemo drugs, cytarabine (ara-C) and an anthracycline drug such as daunorubicin (daunomycin) or idarubicin. Sometimes a third drug, cladribine (Leustatin, 2-CdA), is given as well. The chemo is usually given in the hospital and lasts about a week.
Patients with poor heart function can’t be treated with anthracyclines, so they may be treated with another chemo drug, such as fludarabine (Fludara) or topotecan.
In rare cases where the leukemia has spread to the brain or spinal cord, chemo may also be given into the cerebrospinal fluid (CSF). Radiation therapy might be used as well.
Induction destroys most of the normal bone marrow cells as well as the leukemia cells. Most patients develop dangerously low blood counts at this time, and may be very ill. Most patients need antibiotics and blood product transfusions. Drugs to raise white blood cell counts may also be used. Blood counts tend to stay low for a few weeks. Usually, the patient stays in the hospital during this time.
About 1 or 2 weeks after chemo is done, the doctor will check a bone marrow biopsy. It should show few bone marrow cells (hypocellular bone marrow) and only a small portion of blasts. If the biopsy shows that there are still leukemia cells in the bone marrow, more chemo may be given. Sometimes a stem cell transplant is recommended at this point. If it isn’t clear on the bone marrow biopsy whether the leukemia is still there, another bone marrow biopsy may be done again in about a week.
Over the next few weeks, normal bone marrow cells will return and start making new blood cells. The doctor may check other bone marrow biopsies during this time. When the blood cell counts recover, the doctor will again check cells in a bone marrow sample to see if the leukemia is in remission (blasts make up no more than 5% of the bone marrow).
Remission induction usually does not destroy all the leukemia cells, and a small number often remain. Without consolidation treatment, the leukemia is likely to return within several months.
Consolidation (post-remission therapy)
Induction is considered successful if remission is achieved. Further treatment is then given to try to destroy any remaining leukemia cells and help prevent a relapse. This is called consolidation.
For younger patients, the main options for consolidation therapy are:
- Several cycles of high-dose cytarabine (ara-C) chemo (sometimes known as HiDAC)
- Allogeneic (donor) stem cell transplant
- Autologous stem cell transplant
Consolidation chemo differs from induction therapy in that usually only cytarabine is used. The drug is given at very high doses, typically over 5 days. This is repeated about every 4 weeks, usually for a total of 3 or 4 cycles. Another approach after successful induction therapy is to give very high doses of chemo followed by either an allogeneic (from a donor) or autologous (patient’s own) stem cell transplant. Stem cell transplants have been found to reduce the risk of leukemia coming back more than standard chemo, but they are also more likely to have serious complications, including an increased risk of death from treatment.
Older patients or those in poor health may not be able to tolerate such intensive consolidation treatment. Often, giving them more intensive therapy raises the risk of serious side effects (including treatment-related death) without providing much more of a benefit. These patients may be treated with:
- 1 or 2 cycles of higher dose cytarabine (usually not quite as high as in younger patients)
- 1 or 2 cycles of standard dose cytarabine, possibly along with idarubicin, daunorubicin, or mitoxantrone
- Non-myeloablative stem cell transplant (mini-transplant)
It is not always clear which treatment option is best for consolidation. Each has pros and cons. Doctors look at several different factors when recommending what type of therapy a patient should get. These include:
- How many courses (cycles) of chemo it took to bring about a remission. If it took more than one course, some doctors recommend that the patient get a more intensive program, which might include a stem cell transplant.
- The availability of a brother, sister, or an unrelated donor who matches the patient’s tissue type. If a close enough tissue match is found, an allogeneic (donor) stem cell transplant may be an option, especially for younger patients.
- The potential of collecting leukemia-free bone marrow cells from the patient. If lab tests show that a patient is in remission, collecting stem cells from the patient’s bone marrow or blood for an autologous stem cell transplant may be an option. Stem cells collected from the patient would be purged (treated in the lab to try to remove or kill any remaining leukemia cells) to lower the chances of relapse.
- The presence of one or more adverse prognostic factors, such as certain gene or chromosome changes, a very high initial white blood cell count, AML that develops from a previous blood disorder or after treatment for an earlier cancer, or spread to the central nervous system. These factors might lead doctors to recommend more aggressive therapy, such as a stem cell transplant. On the other hand, for people with good prognostic factors, such as favorable gene or chromosome changes, many doctors might advise holding off on a stem cell transplant unless the disease recurs.
- The patient’s age. Older patients may not be able to tolerate some of the severe side effects that can occur with high-dose chemo or stem cell transplants.
- The patient’s wishes. There are many issues that revolve around quality of life that must be discussed. An important issue is the higher chance of early death from high-dose chemo or a stem cell transplant. This and other issues must be discussed between the patient and the doctor.
Stem cell transplants are intensive treatments with real risks of serious complications, including death, and their exact role in treating AML is not always clear. Some doctors feel that if the patient is healthy enough to withstand the procedure and a compatible donor is available, an allogeneic transplant offers the best chance for long-term survival. Others feel that studies have not yet shown this conclusively, and that in some cases a transplant should be reserved in case the leukemia comes back after standard treatment. Still others feel that stem cell transplants should be given if the leukemia is likely to come back based on certain gene or chromosome changes. Research in this area continues to see which AML patients get the most benefit from stem cell transplant and what is the best transplant procedure.
Treating frail, older adults
Treatment of AML in people under 60 is fairly standard. It involves cycles of intensive chemo, sometimes along with a stem cell transplant (as discussed above). Many patients older than 60 are healthy enough to be treated in the same way, although sometimes the chemo may be less intense. People who are much older or are in poor health may not be able to tolerate this intense treatment. In fact, intense chemo could actually shorten their lives.
In some cases, doctors may recommend low-intensity chemo with a low dose of cytarabine given in cycles. Sometimes, these patients may be treated with other chemo drugs like azacitidine (Vidaza) or decitabine (Dacogen). These drugs aren’t approved to treat AML, but still may be helpful. In some cases, this may induce remission. In others, it may control the leukemia for a time. Treatment of these patients is often not divided into induction and consolidation phases, but it may be given every so often as long as it seems helpful.
Some patients decide against chemo and other drugs and instead choose supportive care. This focuses on treating any symptoms or complications that arise and keeping the person as comfortable as possible.
Last Revised: 02/22/2016