What Is Leukemia?

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

White blood cells help fight infection and protect the body against disease. But in leukemia, some of the white blood cells turn cancerous and don't work as they should. As more cancerous cells form in the blood and bone marrow (spongy tissue inside the bones), there's less room for healthy cells.

The different types of leukemia can be 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 type of white blood cell). It's the most common type of childhood cancer. ALL is also called acute lymphocytic leukemia and acute lymphoid leukemia.

ALL can affect different types of lymphocytes (B-cells or T-cells). Doctors divide acute lymphoblastic leukemia into subtypes based on the type of lymphocytes involved. Most kids with ALL have a B-cell subtype.

Acute lymphoblastic leukemia develops and gets worse quickly. So prompt diagnosis 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 Acute Lymphoblastic Leukemia?

The cause of acute lymphoblastic leukemia is not known. But some risk factors might increase a child's chances of developing it.

Who Gets Acute Lymphoblastic Leukemia?

Acute lymphoblastic leukemia can happen in people of all ages, but is most common in kids ages 2 to 5.

Risk factors for kids include:

  • having an identical twin who had 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 or Down syndrome)
  • getting medicines to suppress the immune system after an organ transplant
  • exposure to X-rays before birth
  • earlier radiation treatment or chemotherapy for other types of cancer

What Are the Signs & Symptoms of Acute Lymphoblastic Leukemia?

All types of leukemia generally have the same symptoms. These include:

  • being very tired, weak, or pale
  • swollen lymph nodes
  • infections (like bronchitis or tonsillitis) that keep coming back
  • a fever
  • night sweats
  • easy bruising or petechiae (tiny red spots on the skin caused by easy bleeding)
  • bone and joint pain
  • belly pain (because cancerous blood cells build up in organs like the kidneys, liver, and spleen)

How Is Acute Lymphoblastic Leukemia Diagnosed?

Doctors use special tests when they suspect leukemia. These include:

  • 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 and how well the organs are working. The shapes and sizes of the blood cells are checked with a microscope.
  • Imaging studies. These may include an X-ray, CT scan, MRI, or ultrasound. These can see whether there's a mass of leukemia cells in the chest that could affect breathing or blood circulation. They also can rule out other possible causes of a child's symptoms.
  • Bone marrow aspiration and biopsy. The doctor puts a needle into a large bone, usually the hip, and removes a small amount of bone marrow. Then the lab does these tests on the bone marrow sample:
    • Flow cytometry tests. Doctors look at the cancer cells and figure out the type and subtype of the leukemia. This is important because treatment differs depending on the type of leukemia.
    • Genetic tests. By looking at the blood or bone marrow, doctors check for changes in the genes. The changes can help doctors figure out the best treatment.
  • Lumbar puncture (spinal tap). The doctor uses a hollow needle to remove a small amount of cerebrospinal fluid (the fluid surrounding the brain and spinal cord) for exam in a lab.

How Is Acute Lymphoblastic Leukemia Treated?


Doctors usually treat children with acute lymphoblastic leukemia with chemotherapy. These special drugs kill cancer cells. Which drugs a child gets and in what combination depends on the subtype of ALL and how aggressive the disease is. How the cancer responds to the initial treatment is also important in choosing the type of chemo.

Doctors can give chemo:

  • through a vein
  • as an injection into a muscle
  • by mouth in pill form
  • with a spinal tap right into the cerebrospinal fluid, where cancerous WBCs can collect

The treatment goal is remission, which is when tests don't find any cancer cells in the body. Then, maintenance chemotherapy is used to keep the child in remission and prevent the cancer from coming back. The child will get maintenance chemo for 2 to 3 years.

Stem Cell Transplants

Kids who have an aggressive type of acute lymphoblastic leukemia might need a stem cell transplant. Also called a bone marrow transplant, this involves:

  • destroying cancer cells, normal bone marrow, and immune system cells with high-dose chemotherapy and/or radiation
  • putting healthy donor stem cells back into the body
  • rebuilding a healthy blood supply and immune system with the new stem cells 

Clinical Trials

Clinical trials are research studies that offer promising new treatments not yet available to the public. Doctors will decide if a child is a good candidate for a clinical trial.

Can Acute Lymphoblastic Leukemia Be Prevented?

In most cases, no one can control the things that trigger acute lymphoblastic leukemia. Studies are looking into the possibility that some environmental things may put a child at risk for ALL.

Prenatal radiation exposure, such as X-rays, may trigger ALL in an unborn baby. Pregnant women and those who think they could be pregnant should tell their doctors before having tests or medical procedures that involve radiation.

Looking Ahead

Learning that a child has cancer is upsetting, and cancer treatment can be stressful for any family.

But remember, 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.

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