Chemotherapy (chemo) is the use of anti-cancer drugs that are injected into a vein, under the skin, or into the cerebrospinal fluid (CSF), or drugs that are taken by mouth to destroy or control cancer cells. Except when given into the CSF, these drugs enter the bloodstream and reach all areas of the body, making this treatment useful for cancers such as leukemia that spread throughout the body.
Chemotherapy is the main treatment for most people with acute myeloid leukemia (AML). Doctors give chemo in cycles, with each period of treatment followed by a rest period to allow the body time to recover. Chemo is often not recommended for patients in poor health, but advanced age by itself is not a barrier to getting chemo.
Treatment of AML is usually divided into 2 phases:
- Induction is the first phase of treatment. The goal is to clear the blood of leukemia cells (blasts) and to reduce the number of blasts in the bone marrow to normal.
- Consolidation is chemo given after the patient has recovered from induction. It is meant to kill the small number of leukemia cells that are still around but can’t be seen (because there are so few of them).
A third phase called maintenance involves giving a low dose of chemo for months or years after consolidation is finished. This is often used for the M3 subtype of AML (also known as acute promyelocytic leukemia, or APL), but it is rarely used for other types of AML.
The chemo drugs used most often to treat AML are cytarabine (cytosine arabinoside or ara-C) and the anthracycline drugs (such as daunorubicin (daunomycin), idarubicin, and mitoxantrone).
Some of the other chemo drugs that may be used to treat AML include:
- Cladribine (Leustatin®, 2-CdA)
- Fludarabine (Fludara®)
- Etoposide (VP-16)
- 6-thioguanine (6-TG)
- Hydroxyurea (Hydrea®)
- Corticosteroid drugs, such as prednisone or dexamethasone (Decadron®)
- Methotrexate (MTX)
- 6-mercaptopurine (6-MP)
- Azacitidine (Vidaza®)
- Decitabine (Dacogen®)
Possible side effects
Chemo drugs attack cells that are dividing quickly, which is why they work against cancer cells. But other cells in the body, such as those in the bone marrow (where new blood cells are made), the lining of the mouth and intestines, and the hair follicles, also divide quickly. These cells are also likely to be affected by chemo, which can lead to side effects.
The side effects of chemo depend on the type and dose of drugs given and how long they are taken. These side effects can include:
- Hair loss
- Mouth sores
- Loss of appetite
- Nausea and vomiting
- Diarrhea or constipation
Chemo drugs also affect the normal cells in bone marrow, which can cause lowering of blood cell counts in AML patients. This can lead to:
- Increased risk of infections (from having too few normal white blood cells)
- Easy bruising or bleeding (from having too few blood platelets)
- Fatigue (from having too few red blood cells)
Most side effects last a short time and go away once treatment is finished. Low blood cell counts can last weeks, but then should return to normal. There are often ways to lessen these side effects. For example, drugs can be given to help prevent or reduce nausea and vomiting. Be sure to ask about medicines to help reduce side effects, and let your doctor or nurse know when you do have side effects so they can be managed effectively.
Drugs known as growth factors, such as G-CSF (filgrastim, Neupogen®) and GM-CSF (sargramostim, Leukine®), are sometimes given to increase the white blood cell counts after chemo, to reduce the chance of infection. However, it’s not clear if they have an effect on treatment success.
If your white blood cell counts are very low during treatment, you can help reduce your risk of infection by carefully avoiding exposure to germs. During this time, your doctor may tell you to:
- Wash your hands often.
- Avoid fresh, uncooked fruits and vegetables and other foods that might carry germs.
- Avoid fresh flowers and plants because they may carry mold.
- Make sure other people wash their hands before they come in contact with you.
- Avoid large crowds and people who are sick.
You may get antibiotics before there are signs of infection or at the earliest sign that an infection may be developing (such as a fever). You may also get drugs that help prevent viral and fungal infections.
Some of the most serious side effects of chemo are caused by low white blood cell counts. Decisions about when a patient can leave the hospital are often influenced by his or her blood counts. Some people find it helpful to keep track of their counts. If you are interested in this, ask your doctor or nurse about your blood cell counts and what these numbers mean.
If your platelet counts are low, you may be given drugs or platelet transfusions to help prevent bleeding. Likewise, shortness of breath and extreme fatigue caused by low red blood cell counts may be treated with drugs or with red blood cell transfusions.
Certain drugs have some specific possible side effects. For example, when used at high doses, cytarabine can cause certain problems, including dryness in the eyes and effects on certain parts of the brain, which can lead to problems with coordination or balance. The drug dose may need to be reduced or stopped altogether if these side effects appear.
Anthracyclines can damage the heart, so they might not be used in someone who already has heart problems.
Other organs that could be damaged by chemo drugs include the kidneys, liver, testicles, ovaries, and lungs. Doctors and nurses carefully monitor treatment to limit the risk of these side effects as much as possible.
If serious side effects occur, the chemo may have to be reduced or stopped, at least for a short time. Careful monitoring and adjustment of drug doses are important because some side effects can be permanent.
Tumor lysis syndrome is another possible side effect of chemo. This can occur in patients who have large numbers of leukemia cells in the body, so it mainly occurs in patients during the induction phase of treatment. When chemo kills these cells, they break open and release their contents into the bloodstream. This can overwhelm the kidneys, which aren’t able to get rid of all of these substances at once. Excess amounts of certain minerals can also affect the heart and nervous system. This can be prevented by giving extra fluids during treatment and by giving certain drugs, such as bicarbonate, allopurinol, and rasburicase, which help the body get rid of these substances.
For more about chemo and its side effects, see the Chemotherapy section of our website.
Last Revised: 02/22/2016