Chemotherapy for Childhood Leukemia

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

The treatment of leukemia uses 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 acute lymphocytic leukemia (ALL) treatment uses lower doses of chemo over a longer period of time (usually 2 to 3 years).

Some of the drugs used to treat childhood leukemia include:

• Vincristine (Oncovin)
• Daunorubicin, also known as daunomycin (Cerubidine)
• Doxorubicin (Adriamycin)
• Cytarabine, also known as cytosine arabinoside or ara-C (Cytosar)
• L-asparaginase (Elspar), PEG-L-asparaginase (pegaspargase, Oncaspar)
• Etoposide (VePesid, others)
• Teniposide (Vumon)
• 6-mercaptopurine (Purinethol)
• 6-thioguanine
• Methotrexate
• Mitoxantrone
• Cyclophosphamide (Cytoxan)
• Prednisone
• Dexamethasone (Decadron, others)

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 chemotherapy

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 can also be affected by chemotherapy, 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
• Increased risk of infections (because of low white blood cell counts)
• Bruising and bleeding easily (from low platelet counts)
• Fatigue (caused by low red blood cell counts)

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 chemotherapy, but they will probably improve as the leukemia cells are killed off and the normal cells in the bone marrow recover.

The side effects above 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 is another possible side effect of chemotherapy. It can happen in patients 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 by giving certain drugs, such as bicarbonate, allopurinol, and rasburicase, which help the body get rid of these substances.

Some chemo drugs can also have specific side effects that are not listed above. 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.

Chemotherapy 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.

Chemo can also cause some long-term side effects. These are discussed in  What Happens After Treatment for Childhood Leukemia?

For more information on chemotherapy, see the Chemotherapy section of our website.