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Acute Lymphoblastic Leukemia (ALL)


What Is Leukemia?

Leukemia is a type of blood cancer that affects the body's white blood cells (WBCs).

Normally, WBCs help fight infection and protect the body against disease. But in leukemia, white blood cells turn cancerous and multiply when they shouldn't. The result is too many immature WBCs, which then interfere with organ function.

The different types of leukemia are classified as either acute (fast growing) or chronic (slow growing).

What Is Acute Lymphoblastic Leukemia (ALL)?

Acute lymphoblastic leukemia (ALL) happens when the body makes too many lymphoblasts (a certain type of white blood cell). Also called acute lymphocytic leukemia and acute lymphoid leukemia, it's the most common type of childhood cancer. Because it develops and gets worse quickly, prompt treatment is very important.

Thanks to advances in therapy and clinical trials, the outlook for kids with ALL is promising. With treatment, most are cured.

What Causes ALL?

The cause of ALL is not known. However, there are risk factors that might increase a child's chance of developing it.

Who Gets ALL?

Kids ages 2 to 5 are more likely to be affected, but people of any age can develop ALL.

Risk factors for kids include:

  • having an identical twin who was diagnosed with the illness before age 6
  • being a fraternal twin and other sibling of a child with leukemia
  • having an inherited genetic problem (such as Li-Fraumeni syndrome, Down syndrome, Klinefelter syndrome, neurofibromatosis, ataxia telangiectasia, or Fanconi anemia)
  • receiving medicines to suppress their immune systems after organ transplants
  • exposure to X-rays before birth
  • prior radiation treatment or chemotherapy for other types of cancer

What Are the Signs and Symptoms of ALL?

All types of leukemia generally have the same symptoms, which include:

  • a fever
  • easy bruising
  • being very tired, weak, or pale
  • swollen lymph nodes
  • recurrent infections (like bronchitis or tonsillitis)
  • bone and joint pain
  • abdominal pain (caused by abnormal blood cells building up in organs like the kidneys, liver, and spleen)

How Is ALL Diagnosed?

Subtypes and Classification

Different types of lymphocytes (B-cells or T-cells) can be affected in ALL. Doctors divide ALL into subtypes based on the lymphocytes involved. Most kids with ALL have a B-cell subtype.

In cancers that create solid tumors, doctors use a staging system to describe the size and progression of the disease. Because leukemia affects the blood and bone marrow, doctors use a classification system instead. ALL usually is considered "newly diagnosed and untreated," "in remission," "refractory" (not responding to treatment), or "recurrent" (the cancer has come back after treatment).

Identifying the ALL accurately is important and requires special tests. A doctor who suspects a child has leukemia might order these tests:

  • Blood tests. Tests such as a complete blood count, liver and kidney function panels, and blood chemistries can give important information about the number of normal blood cells in the body and how well the organs are working. The blood cells are viewed under a microscope to check for abnormal shapes or sizes.
  • Bone marrow aspiration and biopsy. In this procedure, the doctor inserts a needle into a large bone, usually the hip, and removes a small amount of bone marrow to examine for abnormal cells.
  • Imaging studies. These may include an X-ray, CT scan, MRI, or ultrasound to check for an enlarged spleen or liver. These imaging studies are used to see whether there's a mass of leukemia cells in the chest that could interfere with breathing and/or blood circulation, and also to rule out any other possible causes of a child's symptoms.
  • Lumbar puncture. Also called a spinal tap, this procedure uses a hollow needle to remove a small amount of cerebrospinal fluid (the fluid surrounding the brain and spinal cord) for examination in a lab. Cancerous WBCs can collect in this area.
  • Flow cytometry tests. Analyzing the cancer cells lets doctors determine the type and subtype of the leukemia. This is important because treatment varies among different types of leukemia.
  • Chromosomal tests. Analyzing DNA from the blood or bone marrow lets doctors check for the specific genetic changes that identify the subtypes of ALL. This is important because treatments may vary according to subtype.

How Is ALL Treated?

Most children with ALL are treated with chemotherapy (the use of special drugs to kill cancer cells). What drugs are used and in what combination will depend on the subtype of ALL and how aggressive the disease is.

Chemotherapy is given intravenously as an injection into a muscle or orally in pill form. In intrathecal (IT) chemotherapy, a spinal tap delivers the drugs directly to the cerebrospinal fluid, where cancerous WBCs can collect.

After treatment begins, the goal is remission (when there is no longer evidence of cancer cells in the body). Then, chemotherapy typically is used to keep the child in remission.

Maintenance chemotherapy is given in cycles over a period of 2 to 3 years to keep the cancer from coming back. Leukemia will almost always relapse (come back) if this additional chemo isn't given. Sometimes the cancer will return in spite of maintenance chemotherapy. If so, other forms of chemotherapy will be needed.

Kids who have an aggressive type of ALL might need a stem cell transplant (sometimes called a bone marrow transplant). This procedure involves destroying cancer cells, normal bone marrow, and immune system cells with high-dose chemotherapy and then re-introducing healthy donor stem cells into the body. The new stem cells can rebuild a healthy blood supply and immune system.

If a child needs a stem cell transplant, a test (called tissue typing or HLA [human leukocyte antigen] typing) is done to help doctors find a suitable stem cell donor. This works by comparing the proteins on the surface of a child's blood cells with the proteins on a potential donor's cells. The more "HLA markers" a child and donor share, the greater the chance that the transplant will be successful.

Can ALL Be Prevented?

In most cases, neither parents nor children have control over the things that trigger leukemia. Current studies are investigating the possibility that some environmental factors may put a child at risk for the disease.

Because prenatal radiation exposure (such as X-rays) may trigger ALL in a developing fetus, women who are pregnant (or think they could be pregnant) should tell their doctors before having tests or medical procedures that involve radiation.

Looking Ahead

Being told that a child has cancer can be very scary, and the stress of cancer treatment can be overwhelming for any family.

Although you might feel like it at times, you're not alone. To find support, talk to your doctor or a hospital social worker. Many resources are available to help you get through this difficult time.

Reviewed by: Emi H. Caywood, MD
Date reviewed: October 2017

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