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Treatment of most children with acute myelogenous leukemia (AML) is
divided into 2 phases of chemotherapy: induction and consolidation
(intensification). Treatment of the M3 subtype (acute promyelocytic
leukemia, or APL) is slightly different, and is described separately
below. Because of the intensity of treatment and the risk of serious
complications, children with AML should be treated in cancer centers or
hospitals that have experience with this disease.
Induction
Treatment for AML uses combinations of drugs that are
different from those used for ALL. The drugs most often used are
daunorubicin (daunomycin) and cytarabine (ara-C), which are each given
for several days in a row. The schedule of treatment may be repeated in
10 days or 2 weeks, depending on how intense the doctor wants the
treatment to be. A shorter interval between treatments causes more
severe side effects, but may be more effective in killing leukemia
cells.
If the doctors think that the leukemia may not respond to just
2 drugs alone, they may add etoposide and/or 6-thioguanine. Children
with very high numbers of white blood cells or whose leukemia has
certain chromosome abnormalities may fall into this class.
Treatment with these drugs is repeated until the bone marrow
shows no more leukemia. This usually occurs after 2 or 3 treatments.
Preventing relapse in the central nervous system: In most
cases, intrathecal chemotherapy (given directly into the cerebrospinal
fluid, or CSF) is also given to help prevent leukemia from relapsing in
the brain or CSF. Radiation therapy to the brain is used less often.
The risk for recurrence in the brain or CSF is lower in children with
AML than in children with ALL.
Consolidation (Intensification)
This begins after the induction phase, when the bone marrow
has no more visible leukemia cells.
About 1 out of 5 children has a brother or sister who would be
a good stem cell donor. For these children, an allogeneic stem cell
transplant is often recommended. Most studies have found this improves
the chance for long-term survival over chemotherapy alone, although it
is also more likely to cause serious complications. For children with
good prognostic factors, some doctors may recommend just giving
high-dose chemotherapy, and reserving the stem cell transplant in case
the AML relapses.
For most other children, consolidation consists of giving the
chemotherapy drug cytarabine (ara-C) in high doses. Daunorubicin may
also be added. It is usually given for at least several months.
Intrathecal chemotherapy (into the cerebrospinal fluid) is
usually given initially and every 1 to 2 months for as long as
intensification continues.
Maintenance chemotherapy is not needed for children with AML
(other than those with APL - see below).
An important part of treatment for AML is the supportive care
(proper nursing care, nutrition supplement, antibiotic use, and blood
transfusions). Without antibiotic treatment of infections or
transfusion support, children with AML could not expect the current 75%
to 85% remission rate at the end of induction.
Refractory or Recurrent AML
Less than 15% to 20% of children have refractory AML (leukemia
that does not respond to initial treatment). The outlook for the child
who doesn't go into remission is often poor, and doctors may recommend
some type of stem cell transplant if it can be done.
In a recent clinical trial, children who were not in complete
remission after induction chemotherapy were given a drug called
gemtuzumab ozogamicin (Mylotarg) as part of their intensification.
Mylotarg is a chemotherapy drug attached to a manmade antibody. The
antibody is designed to bring the chemotherapy directly to the AML
cells. Early results suggest this treatment may help improve survival
rates for some children with AML.
Generally, the outlook for a child whose AML relapses (comes
back) after treatment is slightly better, but this depends on how long
the initial remission was. In more than half of cases of relapse, a
second remission can be achieved with more chemotherapy. The chance of
getting a second remission is better if the first remission lasted for
at least a year, but long-term second remissions are rare without a
stem cell transplant.
Many different combinations of standard chemotherapy drugs
have been used in these situations, but the results have been mixed.
Most children will be offered a clinical trial that is testing
a new treatment regimen. The hope is that some sort of a remission can
be attained so that an allogeneic stem cell transplant can be done. If
remission is achieved, a stem cell transplant should be considered.
Some doctors may advise an allogeneic stem cell transplant even when
there is no remission. This can sometimes be successful.
Cure Rates for AML
The cure rate for AML (with standard chemotherapy) is 40% to
50%. Treatment of AML with a stem cell transplant from a brother or
sister with the same tissue type results in a higher cure rate of 55%
to 60%.
Revised: 08/19/2007
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