Acute lymphoblastic leukemia (ALL) occurs in people of all ages but is the most common cancer in children, accounting for 75% of all leukemias in children younger than 15 years. ALL most often affects young children between the ages of 2 and 5 years. Among adults, it is somewhat more common in people older than 45.
In ALL, very immature leukemia cells accumulate in the bone marrow, destroying and replacing cells that produce normal blood cells. The leukemia cells are carried in the bloodstream to the liver, spleen, lymph nodes, brain, and testes, where they may continue to grow and divide. However, ALL cells can accumulate anywhere in the body. They can spread to the layers of tissue covering the brain and spinal cord (leukemic meningitis) and cause anemia, liver and kidney failure, and other organ damage.
Early symptoms of ALL result from the inability of the bone marrow to produce enough normal blood cells.
Fever and excessive sweating may indicate infection. A high risk of infection results from too few normal white blood cells.
Weakness, fatigue, and paleness, which indicate anemia, result from too few red blood cells. Some people may have trouble breathing, a rapid heart rate, or chest pain.
Easy bruising and bleeding, sometimes in the form of nosebleeds or bleeding gums, result from too few platelets. In some cases, people may bleed into their brain or abdomen.
Other symptoms occur when leukemic cells invade other organs.
Leukemia cells in the brain may cause headaches, vomiting, stroke, and disturbances of vision, equilibrium, hearing, and facial muscles.
Leukemia cells in the bone marrow may cause bone and joint pain.
A sense of fullness in the abdomen and sometimes pain can result when leukemia cells cause enlargement of the liver and spleen.
Blood tests, such as a complete blood count, can provide the first evidence of ALL. The total number of white blood cells may be decreased, normal, or increased, but the number of red blood cells and platelets is almost always decreased. In addition, very immature white blood cells (blasts) are present in the blood.
A bone marrow examination is almost always done to confirm the diagnosis and to distinguish ALL from other types of leukemia. Blasts are tested for chromosome abnormalities, which helps doctors determine the exact type of the leukemia and what drugs to use to treat it.
Blood and urine tests are done to detect other abnormalities, including electrolyte abnormalities.
Imaging tests may also be needed. Computed tomography (CT) or magnetic resonance imaging (MRI) is done if the person has symptoms that suggest leukemia cells in the brain. CT of the chest may be done to check for leukemia cells in the area around the lungs. CT, MRI, or ultrasonography of the abdomen may be done when internal organs are enlarged. An echocardiogram (ultrasound of the heart) may be done before starting chemotherapy because chemotherapy sometimes affects the heart.
Before treatment was available, most people who had ALL died within months of the diagnosis. Now, nearly 80% of children and 30 to 40% of adults with ALL are cured. For most people, the first course of chemotherapy brings the disease under control (complete remission). Children between the ages of 3 and 9 have the best prognosis. Infants and older adults fare least well. The white blood cell count at the time of diagnosis, whether the leukemia has spread to the brain, and the chromosome abnormalities in the leukemia cells also influence outcome.
Treatment consists of
Chemotherapy is highly effective and is administered in phases:
Induction chemotherapy is the initial phase of treatment. The goal of induction chemotherapy is to achieve remission by destroying leukemia cells so that normal cells can once again grow in the bone marrow. People may need to stay in the hospital for days or weeks, depending on how quickly the bone marrow recovers.
One of several combinations of drugs is used, and doses are repeated for several days or weeks. The specific combination depends on results of the diagnostic tests. One combination consists of prednisone (a corticosteroid) taken by mouth and weekly doses of vincristine (a chemotherapy drug) given with an anthracycline drug (usually daunorubicin), asparaginase, and sometimes cyclophosphamide, given intravenously. New drugs such as immunotherapy (a treatment that uses a person's own immune system to kill cancer cells) and targeted therapy (drugs that attack a cancer cell's innate biological mechanisms) can be used in some patients with ALL.
Treatment of the brain usually begins during induction and may continue during all phases of treatment. Because ALL is likely to spread to the brain, treatment concentrates on treating leukemia that has spread to the brain or on preventing the spread of leukemia cells to the brain. For treatment of leukemia cells in the layers of tissue covering the brain and spinal cord (the meninges), methotrexate, cytarabine, corticosteroids, or a combination are usually injected directly into the cerebrospinal fluid, or high doses of these drugs may be given by vein (intravenously). This chemotherapy may be given in combination with radiation therapy to the brain.
The consolidation and intensification phase continues to treat bone marrow disease. Additional chemotherapy drugs, or the same drugs as were used during the induction phase, may be used a few times over a period of several weeks. For some people who are at high risk of relapse because of particular chromosomal changes found in their leukemia cells, stem cell transplantation once remission occurs.
Further maintenance chemotherapy, which usually consists of fewer drugs, sometimes at lower doses, usually continues for 2 to 3 years.
Older people with ALL may not be able to tolerate the intensive regimen used for younger people. In these people, gentler induction regimens alone (without subsequent consolidation, intensification, or maintenance) is an option. Sometimes, immunotherapy or a gentler form of stem cell transplantation may be an option in some older people.
During all the above phases, blood and platelet transfusions may be necessary to treat anemia and to prevent bleeding, and antimicrobials may be needed to treat infections. Intravenous fluids and therapy with either allopurinol or rasburicase may also be used to help rid the body of harmful substances, such as uric acid, that are released when leukemia cells are destroyed.
Leukemia cells may begin to appear again (a condition termed relapse), often in the blood, bone marrow, brain, or testes. Early reappearance in the bone marrow is particularly serious. Chemotherapy is given again, and although many people respond to this repeat treatment, the disease has a strong tendency to come back again, especially in infants and in adults. When leukemia cells reappear in the brain, chemotherapy drugs are injected into the cerebrospinal fluid 1 or 2 times a week. When leukemia cells reappear in the testes, radiation therapy to the testes is given along with chemotherapy.
For people who have relapsed, high doses of chemotherapy drugs along with allogeneic stem cell transplantation ("allogeneic" means the stem cells are from another person) offers the best chance of cure. But transplantation can be done only if stem cells can be obtained from a person who has a compatible tissue type (human leukocyte antigen [HLA]–matched). The donor is usually a sibling, but cells from matched, unrelated donors (or occasionally partially matched cells from family members or unrelated donors, as well as umbilical stem cells) are sometimes used. Stem cell transplantation is rarely used for people older than 65 because it is much less likely to be successful and side effects are much more likely to be fatal.
New therapies using monoclonal antibodies (proteins that attach specifically to the leukemia cells, tagging them for destruction) are also used in some people with relapsed ALL. An even newer therapy that can be used in some people with relapsed ALL is called chimeric antigen receptor T-cell therapy (CAR-T). This therapy involves modifying a type of lymphocyte (T lymphocytes, also called T cells) from the person who has leukemia so that the new T cells will recognize and attack leukemia cells.
After relapse, additional treatment for people who are unable to undergo stem cell transplantation is often poorly tolerated and ineffective, frequently causing people to feel much sicker. However, remissions can occur. End-of-life care should be considered for people who do not respond to treatment.
The following is an English-language resource that may be useful. Please note that the MANUAL is not responsible for the content of this resource.
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