Treatment of Children With Acute Myeloid Leukemia (AML)

Treatment of most children with acute myeloid leukemia (AML) is divided into 2 main phases of chemotherapy:

• Induction
• Consolidation (intensification)

Because of the intensity of treatment and the risk of serious complications, children with AML need to be treated in cancer centers or hospitals that have experience with this disease.

Induction

The chemo drugs most often used to treat AML are daunorubicin (daunomycin) and cytarabine (ara-C), which are each given for several days in a row. The treatment schedule may be repeated in 10 days or 2 weeks, depending on how intense doctors want the treatment to be. A shorter time between treatments can be more effective in killing leukemia cells, but it can also cause more severe side effects.

Some children with AML may get a dose of the targeted drug gemtuzumab ozogamicin (Mylotarg) along with chemo as part of their induction treatment.

If the doctors think that the leukemia might not respond to just 2 chemo drugs alone, they may add another chemo drug such as etoposide or 6-thioguanine. Children with very high numbers of white blood cells or whose leukemia cells have certain chromosome abnormalities may fall into this group.

Treatment with these chemo drugs is repeated until the bone marrow shows no more leukemia cells. This usually occurs after 2 or 3 cycles of treatment.

Preventing relapse in the central nervous system: Most children with AML will also get intrathecal chemotherapy (given directly into the cerebrospinal fluid, or CSF) to help prevent leukemia from relapsing in the brain or spinal cord. Radiation therapy to the brain is used less often.

Consolidation (intensification)

About 85% to 90% of children with AML go into remission after induction therapy. This means no signs of leukemia are detected using standard lab tests, but it does not necessarily mean that the leukemia has been cured.

Consolidation (intensification) begins after the induction phase. The purpose is to kill any remaining leukemia cells by using more intensive treatment.

Some children have a brother or sister who would be a good stem cell donor. For these children, a stem cell transplant might be recommended once the leukemia is in remission, especially if the AML has some poorer prognostic factors. Most studies have found this improves the chance for long-term survival over chemo alone, but it is also more likely to cause serious complications. For children with good prognostic factors, some doctors may recommend just giving intensive chemotherapy, and reserving the stem cell transplant in case the AML relapses.

For most children without a good stem cell donor, consolidation consists of the chemo drug cytarabine (ara-C) in high doses. Daunorubicin may also be added. It is usually given for at least several months.

If the targeted drug gemtuzumab ozogamicin (Mylotarg) was given during induction, a dose of this drug will likely be given during this phase of treatment as well.

Intrathecal chemo (into the CSF) is usually given every 1 to 2 months for as long as intensification continues.

Maintenance chemo is not needed for children with AML (other than those with APL).

An important part of treatment for AML is supportive care (proper nursing care, nutritional support, antibiotics, and blood transfusions). The intense treatment needed for AML usually destroys much of the bone marrow (causing severe shortages of blood cells) and can cause other serious complications. Without antibiotic treatment of infections or transfusion support, the current high remission rates would not be possible.

Refractory or recurrent AML

Less than 15% of children have refractory AML (leukemia that does not respond to initial treatment). These leukemias are often very hard to cure, and doctors may recommend a stem cell transplant if it can be done.

Generally, the outlook for a child whose AML relapses (comes back) after treatment is slightly better than if the AML never went into remission, but this depends on how long the initial remission was. In more than half of cases of relapse, the leukemia can be put into a second remission with more chemo. 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 chemo drugs have been used in these situations, but the results have been mixed.

Another option for some children with refractory or recurrent AML is treatment with the targeted drug gemtuzumab ozogamicin (Mylotarg). 

Most children whose leukemia has relapsed are good candidates for clinical trials testing new treatment regimens. The hope is that some sort of a remission can be attained so that a stem cell transplant can be considered. Some doctors may advise a stem cell transplant even if there is no remission. This can sometimes be successful.