What determines the type of treatment?
The type of treatment is based upon certain factors of the patient and leukemia. These include:
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Age of the patient at diagnosis. Children less than one year of age or older than 10 years of age at diagnosis require more aggressive treatment for cure.
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The white blood count at diagnosis. Children with a white blood count greater than 50,000 require more aggressive treatment.
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Subtype of leukemia. There are several different types of ALL. “B cell precursor” is the most common; “T cell” is less common.
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Central nervous system disease. Children with leukemia cells (blasts) in the spinal fluid at diagnosis require more aggressive treatment.
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Chromosomal alterations in the leukemia cell: Cancer cells often display genetic mistakes that have been acquired, meaning that they were not passed down from the parents to the child. At least 60% of ALL cases include such abnormalities. These can affect the type of treatment; in both favorable and unfavorable ways, depending on their type.
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Response to therapy: Children whose leukemia responds more slowly to initial treatment require more aggressive treatment. Minimal residual disease may be used in some studies to detect residual leukemia that cannot be seen under a microscope. The results of this test may also change the type of treatment.
ALL is a cancer of the blood, so treatment is systemic (affects the entire body). Chemotherapy is the mainstay of treatment.
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Induction: The first phase of treatment. Thisusually lasts four weeks. Children receive three or four drugs by mouth and intravenously, and medications delivered into the spinal fluid (intrathecal delivery). The combination of drugs depends upon the leukemia factors as above. The goal of this phase is to kill the leukemia cells and allow normal blood cells to return.
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A bone marrow aspirate is performed at the end of this phase. The bone marrow is looked at under a microscope, and is expected to show only normal cells. This is calledremission. This does not mean that the child is cured, because without further treatment the disease will return. Other tests (such as minimal residual disease) may be performed on the bone marrow and may be more sensitive at finding leukemia cells than looking under a microscope.
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Consolidation: The second phase of treatment. This phase lasts from four to six weeks. Different drugs from those used during Induction are given by mouth and intravenously. This is to kill leukemia cells that may remain after the drugs used in induction. During this phase, another main focus is on treating and preventing the growth of leukemia cells within the central nervous system (CNS prophylaxis). To accomplish this, spinal taps with intrathecal chemotherapy (directly into the spinal fluid) are performed weekly. For certain types of leukemia, or if leukemia cells were present in the spinal fluid at the time of diagnosis, radiation therapy may be given to the brain and the spinal column during this phase.
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Delayed intensification: This is a phase that includes medicines similar to those given in Induction and Consolidation. This has been shown to be helpful in preventing leukemia from returning. The exact timing of the doses and the specific drugs used depend upon the individual characteristics of a particular child’s disease.
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Maintenance: The final phase of treatment. This phase of therapy lasts two or three years. Maintenance is much less intensive than the previous treatment and consists mostly of oral medications given at home. There are also intermittent intravenous and intrathecal medications given throughout this phase.
More information about chemotherapy
What is the cure rate for children with ALL?
The overall cure rate for ALL remains one of the best among all human cancers. Currently, approximately 75% of children are cured, meaning that after treatment, their cancer never comes back. More recurrences (relapses) occur on therapy or within two years of treatment discontinuation. Late relapses (beyond 5 years) are rare.
What if the leukemia comes back?
If the leukemia returns, another remission will often be achieved with more aggressive therapy. Many patients will stay in another remission with additional chemotherapy, but a blood or marrow transplant may be recommended for some patients.
Additional information on relapse
Additional information about blood or marrow transplant
William Carroll, MD, New York University Medical Center
Reviewed and edited by the
CureSearch.org Medical Editorial Board
September 2006