Chemotherapy and targeted therapy for childhood leukemia
Chemotherapy uses anticancer, or cytotoxic, drugs to destroy cancer cells. Most children with leukemia have chemotherapy. The healthcare team will consider your child’s needs to plan the drugs, doses and schedules of chemotherapy. Your child may also receive other treatments.
Chemotherapy is given for different reasons. A child with leukemia may have chemotherapy to:
- destroy all the leukemia cells, or blasts, in the bone marrow and lymphatic tissue to bring about remission
- kill any leukemia cells in the brain or spinal cord (called the central nervous system, or CNS)
- return blood cell production to normal
Chemotherapy is usually a systemic therapy. This means that the drugs travel through the bloodstream to reach and destroy leukemia cells all over the body, including those that may have spread to other parts of the body through the blood. Systemic chemotherapy to treat childhood leukemia may be given by mouth or by a needle into a vein (intravenous) or muscle (intramuscular injection). To allow drugs to be given safely, the doctor may place a special device called a central venous catheter. The device is usually put in place in a short operation at the start of chemotherapy and is left in place until treatment is finished. Find out more about central venous catheter.
Chemotherapy may also be a regional therapy, which means that it is given to a specific area of the body. Regional chemotherapy may be given directly into the brain and spinal cord, or central nervous system (CNS). This is called intrathecal chemotherapy. It is given to prevent or treat the spread of leukemia to the CNS.
In general, treatment for acute myelogenous leukemia (AML) uses higher doses of chemotherapy over a shorter period of time (less than a year). Acute lymphoblastic leukemia (ALL) is usually treated with lower doses of chemotherapy over a longer period of time (usually 2–4 years).
Drugs, doses and schedules vary from child to child. The type and intensity (dose and schedule) of the chemotherapy depends on:
- type and subtype of leukemia
- chromosome or gene abnormalities
- prognostic factors
- level of risk
- age of the child
Chemotherapy drugs used for childhood leukemia
Chemotherapy drugs used to treat childhood leukemia are:
- vincristine (Oncovin)
- daunorubicin (Cerubidine, daunomycin)
- doxorubicin (Adriamycin)
- cytarabine (Cytosar, Ara-C)
- asparaginase (Kidrolase), asparaginase erwinia (Erwinase) or pegaspargase (Oncaspar)
- etoposide (Vepesid, VP-16)
- teniposide (Vumon, VM-26)
- mercaptopurine (Purinethol, 6-MP)
- thioguanine (Lanvis, 6-TG)
- mitoxantrone (Novantrone)
- cyclophosphamide (Cytoxan, Procytox)
Steroids, such as prednisone or dexamethasone (Decadron, Dexasone), may be given with the above combinations of chemotherapy drugs.
The most common combinations of drugs used in induction chemotherapy to treat childhood leukemia are:
- vincristine, dexamethasone and asparaginase
- vincristine, dexamethasone, asparaginase and either daunorubicin or doxorubicin
If childhood leukemia does not respond to drugs used in earlier treatments, or if it recurs, a repeat course of the original protocol may be used. Sometimes the doses of the drugs are increased.
Central nervous system (CNS) therapy
Leukemia cells, or blasts, can spread to the central nervous system (CNS). They may be present in the CNS at diagnosis or they may spread to the CNS as the disease progresses. Drugs are given directly into the spaces containing cerebrospinal fluid (CSF) to prevent leukemia cells from spreading to the CNS or to treat leukemia cells in the CNS. This is called intrathecal chemotherapy. The doctor will use a lumbar puncture, or spinal tap, to inject the drugs.
The most common chemotherapy drugs used for CNS therapy to treat or prevent leukemia cells in the CNS are:
Targeted therapy is a type of treatment that uses drugs to target specific molecules (usually proteins) involved in cancer cell growth while limiting harm to normal cells. Targeted therapy may be used to treat children with childhood leukemia who are positive for the Philadelphia chromosome (Ph+). It may be given:
- as a primary treatment
- during any phase of treatment
The most common targeted therapy drug used is imatinib (Gleevec). Another targeted therapy drug that may be used is dasatinib (Sprycel). These drugs are taken by mouth (orally) once a day.
Information about specific cancer drugs
The following websites have information about specific drugs used to treat cancer in children.
- Cancer Care Ontario (CCO) Drug Formulary is a searchable database of drugs used to treat cancer.
- British Columbia Cancer Agency (BCCA) Drug Index (Professional) provides is a list of drugs used to treat cancer and basic information about uses and doses.
Questions to ask about chemotherapy
Establishing a national caregivers strategy
The Canadian Cancer Society is actively lobbying the federal government to establish a national caregivers strategy to ensure there is more financial support for this important group of people.