Types of Treatment
Acute lymphoblastic leukemia is a cancer of the blood, so treatment is systemic, meaning it affects the entire body. At the time of diagnosis, the healthcare team will insert a central line to provide treatment. Chemotherapy is the mainstay of treatment.
The first phase of treatment usually lasts four weeks. Children receive three or four drugs by mouth, intravenously (into a vein), or into the spinal fluid (intrathecal delivery). The combination of drugs can vary depending on the particular diagnosis. The goal of this phase is to kill the leukemia cells and allow normal blood cells to return.
A bone marrow aspirate is performed at the end of this phase. The bone marrow is examined under a microscope. Often after the first round of chemotherapy, doctors will see no evidence of leukemia cells in the bone marrow. At that point, the disease is considered in remission. However, it is crucial to continue treatment, since there may be some cancer cells left over in the bone marrow or blood that could continue to replicate and allow the cancer to spread. However, remission is a very important first step on the road towards being cured. Nearly 98 of every 100 children with acute lymphoblastic leukemia will enter remission at the end of the first month of treatment.
The second phase of treatment lasts from 12-16 weeks. Different drugs from those used during Induction are given by mouth and intravenously.
The purpose of the consolidation phase is to kill leukemia cells that may remain after the drugs used in induction. 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. In most cases, part of the consolidation phase will include treatment with the chemotherapy drug methotrexate.
This eight-week phase of treatment will include the use of the chemotherapy agent methotrexate. Methotrexate is given intravenously, either at lower doses in the clinic or at higher doses that require a 2-3 day stay in the hospital.
This 8-week phase of treatment 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.
The final phase of treatment 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.
- Radiation to the brain: Most of the chemotherapy drugs used to treat acute lymphoblastic leukemia don’t get into the brain and spinal fluid very well. Because of this, special approaches have to be used to kill ALL cells in these areas. All children with acute lymphoblastic leukemia receive intrathecal chemotherapy given into the spinal fluid during a lumbar puncture. In some cases, radiation therapy is also delivered to the brain. Radiation treatments are usually given 5 days a week for about 2 weeks.
- Radiation to the testicles: In most cases, acute lymphoblastic leukemia that is present in the testicles at diagnosis goes away quickly during the first month of treatment. If this does not happen and leukemia cells are present in the testicles at the end of Induction therapy, then radiation therapy to the testicles may be needed. These treatments are usually given 5 days/week for about 2 weeks.
- Surgery: In general, acute lymphoblastic leukemia is not treated with surgery, although operations may need to be done to put in a central line or to perform biopsies.
- Targeted therapy: For some types of acute lymphoblastic leukemia, new “targeted” therapies have been developed that are added to chemotherapy. Right now, this mainly applies to a rare type of ALL called “Philadelphia chromosome positive ALL.” In the future, such therapies may be available for more types of acute lymphoblastic leukemia.
- Bone marrow stem cell transplant: Only a small percentage of children’s ALL cases are treated with bone marrow transplant at the time of initial diagnosis. ALL patients that have particularly high risk mutations in their leukemia cells or that have a poor response to induction may require bone marrow transplant. This type of treatment is used more frequently to treat ALL that has relapsed one or more times.