Treatment for acute lymphoblastic leukemia--also called acute lymphocytic leukemia, or ALL--involves several approaches that are used in combination. The decision as to the specific types of treatment is driven by the age of the patient and the stage of the cancer. Unlike chronic leukemias, treatment for ALL begins immediately after diagnosis. While the initial goal of therapy is to induce a remission, subsequent goals involve sustaining that remission and preventing relapse.
Mechanism of Action
The Leukemia and Lymphoma Society reports that some of the drugs used to treat ALL are clofarabine, cytarabine, daunorubicin, methotrexate, mitoxantrone, cyclophosphamide, vincristine, pegaspargase, imatinib mesylate, prednisone and dexamethasone. Many of these drugs are used in combination. Although these drugs have different mechanisms of action, all inhibit the reproduction of leukemia cells. For example, vincristine works by stopping mitosis. Methotrexate prevents the synthesis of purines, which are necessary to make DNA. Petaspargase works differently--it blocks protein synthesis by depleting the cells of an essential amino acid.
Routes of Administration
The route of administration depends upon the particular drug. Some drugs can be taken orally and others are given intravenously. The National Cancer Institute explains that oral or intravenous administration is called systemic therapy. Systemic therapy differs from local application of drugs. Local use may involve administering the drug by injection or via a catheter into a particular part of the body such as the abdominal cavity, where it exerts a local effect.
Blood Brain Barrier Issues
The blood brain barrier is a chemical gradient that prevents most drugs from reaching the brain or the cerebrospinal fluid. While the blood brain barrier is a distinct advantage that prevents the brain from being injured, it creates problems in the treatment of acute lymphoblastic leukemia because leukemic cells can hide out in the brain or the cerebrospinal fluid. The National Cancer Institute explains that central nervous system sanctuary therapy involves the direction of radiation or drugs to areas that are protected by the blood brain barrier. Drugs are administered through the membranes that encase the brain and the spinal cord. Radiation is specifically directed toward these areas.
Side Effects
The Leukemia and Lymphoma Society explains that some of the more common side effects of chemotherapy used to treat ALL include hair loss, nausea, vomiting, sores in the mouth, diarrhea and rashes. Anemia can also be a problem, as can low white cell counts. Drugs can be given to minimize nausea and vomiting.
Side effects of radiation include fatigue, radiation burns and low white cell counts.
Bone Marrow Transplant
It has become popular to refer to bone marrow transplants as stem cell transplants because the transplanted cells are stem cells. Bone marrow transplants make the use of very high-dose chemo possible.
Stem cells are taken from the bone marrow of a donor or in some instances, from the marrow of the patient. If the cells are taken from the patient, they are first purged of any cancer cells. High doses of chemo are given with the goal of killing off all the cells in the patient's bone marrow. Afterwards, these cells are repopulated using the stem cells as starter cells.
When the procedure is done using the patient's own cells, it is called an autologous stem cell transplant.
