Childhood acute lymphoblastic leukemia (ALL) is a type of cancer in which the bone marrow makes too many immature lymphocytes (a type of white blood cell).
Childhood acute lymphoblastic leukemia (also called acute lymphocytic leukemia or ALL) is a cancer of the blood and bone marrow. This type of cancer usually gets worse quickly if it is not treated. It is the most common type of cancer in children.
Normally, the bone marrow makes blood stem cells (immature cells) that become mature blood cells over time. A blood stem cell may become a myeloid stem cell or a lymphoid stem cell.
A myeloid stem cell becomes one of three types of mature blood cells:
- Red blood cells that carry oxygen and other substances to all tissues of the body.
- Platelets that form blood clots to stop bleeding.
- White blood cells that fight infection and disease.
A lymphoid stem cell becomes a lymphoblast cell and then one of three types of lymphocytes (white blood cells):
- B lymphocytes that make antibodies to help fight infection.
- T lymphocytes that help B lymphocytes make the antibodies that help fight infection.
- Natural killer cells that attack cancer cells and viruses.
In ALL, too many stem cells become lymphoblasts, B lymphocytes, or T lymphocytes. These cells are also called leukemia cells. These leukemia cells do not work like normal lymphocytes and are not able to fight infection very well. Also, as the number of leukemia cells increases in the blood and bone marrow, there is less room for healthy white blood cells, red blood cells, and platelets. This may lead to infection, anemia, and easy bleeding.
Family history and exposure to radiation may affect the risk of developing childhood ALL.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn’t mean that you will not get cancer. Talk with your doctor if you think you may be at risk. Possible risk factors for ALL include the following:
- Having a brother or sister with leukemia.
- Being white or Hispanic.
- Living in the United States.
- Being exposed to x-rays before birth.
- Being exposed to radiation.
- Past treatment with chemotherapy or other drugs that weaken the immune system.
- Having certain in genes or genetic disorders, such as Down syndrome.
Possible signs of childhood ALL include fever and bruising.
These and other symptoms may be caused by childhood ALL. Other conditions may cause the same symptoms. Check with your doctor if you have any of the following problems:
- Fever
- Easy bruising or bleeding
- Petechiae (flat, pinpoint spots under the skin caused by bleeding)
- Bone or joint pain
- Painless lumps in the neck, underarm, stomach, or groin
- Pain or feeling of fullness below the ribs
- Weakness or feeling tired, or looking pale
- Loss of appetite
Tests that examine the blood and bone marrow are used to detect (find) and diagnose childhood ALL.
The following tests and procedures may be used:
- Physical exam and history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
- Complete blood count (CBC) with differential: A procedure in which a sample of blood is drawn and checked for the following:
- The number of red blood cells and platelets.
- The number and type of white blood cells.
- The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
- The portion of the sample made up of red blood cells.
- Bone marrow aspiration and biopsy: The removal of bone marrow, blood, and a small piece of bone by inserting a hollow needle into the hipbone or breastbone. A pathologist views the bone marrow, blood, and bone under a microscope to look for signs of cancer.
- Cytogenetic analysis: A laboratory test in which the cells in a sample of blood or bone marrow are viewed under a microscope to look for certain changes in the chromosomes in the lymphocytes. For example, in Philadelphia chromosome-positive ALL, part of one chromosome is moved to another chromosome. This is called the “Philadelphia chromosome.” Other tests, such as fluorescence in situ hybridization (FISH), may also be done to look for certain changes in the chromosomes.
- Immunophenotyping: A test in which the cells in a sample of blood or bone marrow are looked at under a microscope to find out if malignant lymphocytes (cancer) began from the B lymphocytes or the T lymphocytes.
- Blood chemistry studies: A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it.
- Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
Certain factors affect prognosis (chance of recovery) and treatment options.
The prognosis (chance of recovery) and treatment options may depend on:
- Age at diagnosis and race.
- The number of white blood cells at diagnosis.
- How quickly and how low the leukemia cell count drops after initial treatment.
- Whether the leukemia cells began from the B lymphocytes or the T lymphocytes.
- Whether there are certain changes in the chromosomes of lymphocytes.
- Whether the leukemia has spread to the brain and spinal cord.
- Whether the child has Down syndrome.
If leukemia recurs (comes back) after initial treatment, the prognosis and treatment options may depend on:
- How long it is between the end of initial treatment and when the leukemia recurs.
- Whether the leukemia recurs in the bone marrow or outside the bone marrow.
Stages of Childhood Acute Lymphoblastic Leukemia
Once childhood ALL has been diagnosed, tests are done to find out if the cancer has spread to the central nervous system (brain and spinal cord), testicles, or to other parts of the body.
The extent or spread of cancer is usually described as stages. For childhood acute lymphoblastic leukemia (ALL), risk groups are used instead of stages. The following tests and procedures may be used to determine the risk group:
- Lumbar puncture: A procedure used to collect cerebrospinal fluid from the spinal column. This is done by placing a needle into the spinal column. This procedure is also called an LP or spinal tap.
- Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body. The chest x-ray is done to see if leukemia cells are forming a mass in the middle of the chest.
- Testicular biopsy: The removal of cells or tissues from the testicles so they can be viewed under a microscope by a pathologist to check for signs of cancer. This procedure is done only if there seems to be anything unusual about the testicles during the physical exam.
There are three ways that cancer spreads in the body.
When cancer cells spread outside the blood, a solid tumor may form. This process is called metastasis. The three ways that cancer cells spread in the body are:
- Through the blood. Cancer cells travel through the blood, invade solid tissues in the body, such as the brain or heart, and form a solid tumor.
- Through the lymph system. Cancer cells invade the lymph system, travel through the lymph vessels, and form a solid tumor in other parts of the body.
- Through solid tissue. Cancer cells that have formed a solid tumor spread to tissues in the surrounding area.
The new (metastatic) tumor is the same type of cancer as the primary cancer. For example, if leukemia cells spread to the brain, the cancer cells in the brain are actually leukemia cells. The disease is metastatic leukemia, not brain cancer.
In childhood ALL, risk groups are used instead of stages.
Because ALL is a disease of the blood cells, it has already spread throughout the body at diagnosis. There is no staging system for ALL. Risk groups are used to plan treatment.
Risk groups are described as:
- Standard (low) risk: Includes children aged 1 to less than 10 years who have a white blood cell count of less than 50,000/µL at diagnosis.
- High risk: Includes children younger than 1 year or 10 years and older and children who have a white blood cell count of 50,000/µL or more at diagnosis.
Other factors that affect the risk group include the following:
- Whether the leukemia cells formed from B lymphocytes or T lymphocytes.
- Whether there are certain changes in the chromosomes of the lymphocytes.
- How quickly the leukemia responds to initial therapy.
It is important to know the risk group in order to plan treatment. Children with high-risk ALL usually receive more aggressive treatment than children with standard risk ALL.
Treatment Options for Childhood Acute Lymphoblastic Leukemia
For some types or stages of cancer, there may not be any trials listed. Check with your doctor for clinical trials that are not listed here but may be right for you.
Newly Diagnosed Childhood Acute Lymphoblastic Leukemia
Treatment of childhood acute lymphoblastic leukemia (ALL) during the induction, consolidation /intensification, and maintenance phases may include the following:
- Combination chemotherapy. CNS sanctuary therapy with intrathecal chemotherapy and high-dose chemotherapy. Sometimes radiation therapy to the brain may be given.
- Combination chemotherapy followed by stem cell transplant using stem cells from a donor.
- A clinical trial of a new combination chemotherapy and intrathecal chemotherapy regimen given with or without radiation therapy and/or stem cell transplant. The chemotherapy dose and/or schedule may vary depending on the patient’s risk group after induction therapy.
- A clinical trial of new anticancer drugs.
Childhood Acute Lymphoblastic Leukemia Subgroups
Treatment of T-cell childhood acute lymphoblastic leukemia (ALL) may include the following:
- Combination chemotherapy. CNS sanctuary therapy with intrathecal chemotherapy and radiation therapy to the brain may also be given.
- A clinical trial studying a new anticancer drug, the doses of certain anticancer drugs, and the use of radiation therapy to the brain.
- A clinical trial of new anticancer drugs.
Treatment of infants with ALL may include the following:
- Combination chemotherapy. CNS sanctuary therapy with intrathecal chemotherapy may also be given
- Chemotherapy followed by a donor stem cell transplant has been studied but it is not known if this treatment improves survival.
- A clinical trial of chemotherapy followed by a donor stem cell transplant for infants with certain gene changes.
- A clinical trial of combination chemotherapy and targeted therapy with a tyrosine kinase inhibitor.
Treatment of ALL in older children and teenagers may include the following:
- Combination chemotherapy using stronger doses of anticancer drugs than those used for young children.
- A clinical trial of a new combination chemotherapy regimen.
- A clinical trial studying a new anticancer drug, the doses of certain anticancer drugs, and the use of radiation therapy to the brain.
Treatment of Philadelphia chromosome -positive childhood ALL may include the following:
- Combination chemotherapy followed by stem cell transplant using stem cells from a donor.
- Combination chemotherapy followed by targeted therapy with a tyrosine kinase inhibitor (imatinib mesylate).
- A clinical trial of combination chemotherapy and a new tyrosine kinase inhibitor, with or without stem cell transplant.
Recurrent Childhood Acute Lymphoblastic Leukemia
Standard treatment of recurrent childhood acute lymphoblastic leukemia (ALL) for leukemia that comes back in the bone marrow may include the following:
- Combination chemotherapy.
- Chemotherapy with or without total-body irradiation followed by a stem cell transplant, using stem cells from a donor.
Standard treatment of recurrent childhood acute lymphoblastic leukemia (ALL) for leukemia that comes back outside the bone marrow may include the following:
- Chemotherapy and radiation therapy for cancer that comes back in the testicles only.
- Combination chemotherapy and intrathecal chemotherapy with radiation therapy to the brain and/or spinal cord for cancer that comes back in the brain and spinal cord only.
Some of the treatments being studied in clinical trials for recurrent childhood ALL include the following:
- New anticancer drugs and new combination chemotherapy treatments.
- Combination chemotherapy and new kinds of targeted therapies.
Note that the specific treatment plan will depend on the age of the child, the type and stage of the leukemia, and other factors. With appropriate treatment, the outlook for children with ALL is generally good, with a high rate of remission and long-term survival.