Chemotherapy for Childhood Leukemia

Chemotherapy (chemo) is the main treatment for most childhood leukemias. This is treatment with anti-cancer drugs that are given in a vein (IV), in a muscle, in the cerebrospinal fluid (CSF) around the brain and spinal cord, or are taken by mouth. Except when given in the CSF, chemo drugs enter the bloodstream and reach all areas of the body, making this treatment very useful for cancers such as leukemia.

Leukemia is treated with combinations of several chemo drugs. Doctors give chemo in cycles, with each period of treatment followed by a rest period to give the body time to recover.

In general, treatment for acute myeloid leukemia (AML) uses higher doses of chemo over a shorter period of time (usually less than a year), and treatment for acute lymphocytic leukemia (ALL) uses lower doses of chemo over a longer period of time (usually 2 to 3 years).

Some of the chemo drugs used to treat childhood leukemia include:

• Vincristine
• Daunorubicin, (daunomycin)
• Doxorubicin (Adriamycin)
• Idarubicin
• Cytarabine (cytosine arabinoside or ara-C)
• L-asparaginase, PEG-L-asparaginase (pegaspargase)
• Etoposide
• 6-mercaptopurine (6-MP)
• 6-thioguanine (6-TG)
• Methotrexate
• Mitoxantrone
• Cyclophosphamide
• Corticosteroid drugs such as prednisone, prednisolone, dexamethasone, or hydrocortisone

Children will probably get several of these drugs at different times during the course of treatment, but they do not get all of them.

Possible side effects of chemo

Chemo drugs can affect some normal cells in the body, which can lead to side effects.

The side effects of chemo depend on the type and dose of drugs given and the length of treatment. These side effects can include:

• Hair loss
• Mouth sores
• Loss of appetite
• Diarrhea
• Nausea and vomiting

Chemo drugs also affect the normal cells in bone marrow, which can lower blood cell counts. This can lead to:

• Increased risk of infections (from having too few normal white blood cells)
• Bruising and bleeding easily (from having too few blood platelets)
• Fatigue (from having too few red blood cells)

The problems with blood cell counts are often caused by the leukemia itself at first. They might get worse during the first part of treatment because of the chemo, but they will probably improve as the leukemia cells are killed off and the normal cells in the bone marrow recover.

Most side effects usually go away when treatment is finished. There are often ways to reduce these side effects. For instance, drugs can be given to help prevent or reduce nausea and vomiting. Other drugs known as growth factors can be given to help keep the blood cell counts higher.

Tumor lysis syndrome: This side effect of chemo can happen in children who had large numbers of leukemia cells in the body before 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. Too much of certain minerals can also affect the heart and nervous system. This problem can be prevented by making sure the child gets lots of fluids during treatment and certain drugs, such as bicarbonate, allopurinol, and rasburicase, which help the body get rid of these substances.

Some chemo drugs can also have other specific side effects. For example:

• Vincristine can damage nerves, which can lead to numbness, tingling, or weakness in hands or feet (known as peripheral neuropathy).
• L-asparaginase and PEG-L-asparaginase can increase the risk of blood clots.

Some chemo drugs can also cause late or long-term side effects, such as effects on growth and development, effects on fertility later in life, or an increased risk of getting a second cancer (often AML). For more on this, see Living as a Childhood Leukemia Survivor.

Be sure to ask your child’s doctor or nurse about any specific side effects you should watch for and about what you can do to help reduce these side effects.

Chemo given directly into the cerebrospinal fluid (CSF) around the brain and spinal cord (known as intrathecal chemotherapy) can have its own side effects, although these are not common. Intrathecal chemo may cause trouble thinking or even seizures in some children.