What is leukemia in children?

Leukemia is cancer of the blood. It’s the most common form of cancer in childhood. The cancer cells grow in bone marrow and go into the blood. The bone marrow is the soft, spongy center of some bones. It makes blood cells. When a child has leukemia, the bone marrow makes abnormal blood cells that don’t mature. The abnormal cells are usually white blood cells (leukocytes). The bone marrow also makes fewer healthy cells. The abnormal cells reproduce very quickly. They don’t work the same as healthy cells. A child has symptoms when he or she has more abnormal cells and less normal cells.

The types of blood cells include:

• Red blood cells (erythrocytes). Red blood cells carry oxygen. When a child has a low level of healthy red blood cells, this is called anemia. A child may feel tired, weak, and short of breath.

• Platelets (thrombocytes). Platelets help with blood clotting and stop bleeding. When a child has low levels of platelets, he or she bruises and bleeds more easily.

• White blood cells (leukocytes). These fight infection and other disease. When a child has low levels of white blood cells, he or she is more likely to have infections. The types of leukocytes are:

• Lymphocytes. There are 2 types: B lymphocytes and T lymphocytes. These cells grow from lymphoblasts in the bone marrow.

• Granulocytes. There are 3 types: neutrophils, basophils, and eosinophils. These cells grow from myeloblasts in the bone marrow.

• Monocytes. These cells grow from monoblasts in the bone marrow.

There are different types of leukemia in children. Most types are either acute or chronic. Acute develops quickly, over days or weeks. Chronic develops more slowly, over months or years. Some of the types of leukemia that occur in children include:

• Acute lymphocytic (lymphoblastic) leukemia (ALL). This is the most common type of leukemia in children. It starts from the lymphoblasts, the cells that form lymphocytes in the bone marrow.

• Acute myelogenous (myeloid, myelocytic, non-lymphocytic) leukemia (AML). This is the second most common type of leukemia in children. It starts from the myeloblasts or myeloid cells that form many white blood cells, plus red blood cells and platelets. 

• Hybrid or mixed lineage leukemia. This type is rare. It is a mix of ALL and AML.

• Chronic myelogenous leukemia (CML). This type is also rare in children.  Like AML, it starts from the myeloblasts or myeloid cells that form many white blood cells, plus red blood cells and platelets. 

• Chronic lymphocytic leukemia (CLL). This type is extremely rare in children. Like ALL, it starts from the lymphoblasts, the cells that grow lymphocytes in the bone marrow.

• Juvenile myelomonocytic leukemia (JMML). This is a rare type of cancer that doesn’t grow quickly (acute) or slowly (chronic). It also starts from myeloblasts or myeloid cells. 

What causes leukemia in children?

The exact cause of leukemia in children is not known. There are certain conditions passed on from parents to children (inherited) that increase the risk for childhood leukemia. But, most childhood leukemia is not inherited. Researchers have found changes (mutations) in genes of the bone marrow cells. These changes may occur early in a child's life or even before birth. But they may occur by chance (sporadic).

Who is at risk for childhood leukemia?

The risk factors for childhood leukemia include:

• Exposure to high levels of radiation

• Having certain inherited syndromes, such as Down syndrome and Li-Fraumeni syndrome

• Having an inherited condition that affects the body's immune system

• Having a brother or sister with leukemia

What are the symptoms of leukemia in children?

The symptoms depend on many factors. The cancer may be in the bone marrow, blood, and other tissue and organs. Other tissue and organs may be affected. These may include the lymph nodes, liver, spleen, thymus gland, brain, spinal cord, gums, and skin.

Symptoms can occur a bit differently in each child. They can include:

• Pale skin

• Feeling tired, weak, or cold

• Dizziness

• Headaches

• Shortness of breath, trouble breathing

• Frequent or long-term infections

• Fever

• Easy bruising or bleeding, such as nosebleeds or bleeding gums

• Bone or joint pain

• Belly (abdominal) swelling

• Poor appetite

• Weight loss

• Swollen lymph glands (nodes)

The symptoms of leukemia can be like other health conditions. Make sure your child sees a healthcare provider for a diagnosis.

How is leukemia diagnosed in children?

Your child's healthcare provider will ask many questions about your child's symptoms. He or she will examine your child. Your child's healthcare provider may recommend blood tests and other tests. A complete blood count (CBC) provides the number of red blood cells, different types of white blood cells, and platelets. If the results are abnormal, your child's healthcare provider may recommend that your child see a pediatric cancer specialist (pediatric oncologist). The oncologist may want your child to have additional tests including:

• Bone marrow aspiration or biopsy. Bone marrow is found in the center of some bones. It’s where blood cells are made. A small amount of bone marrow fluid may be taken. This is called aspiration. Or solid bone marrow tissue may be taken. This is called a core biopsy. Bone marrow is usually taken from the hip bone. This test may be done to see if cancer cells have reached the bone marrow.

• Blood tests. Tests like flow cytometry and immunohistochemistry. These tests determine the exact type of leukemia. DNA and chromosome tests may also be done.

• CT scan. This test uses a series of X-rays and a computer to make detailed images of the body.

• MRI. This test uses large magnets, radio waves, and a computer to make detailed images of the inside of the body.

• Positron emission tomography (PET) scan. For this test, a radioactive sugar is injected into the bloodstream. Cancer cells use more sugar than normal cells, so the sugar will collect in cancer cells. A special camera is used to see where the radioactive sugar is in the body. A PET scan can sometimes spot cancer cells in different areas of the body, even when they can’t be seen by other tests. This test is often used in combination with a CT scan. This is called a PET/CT scan.

• X-ray. An X-ray uses a small amount of radiation to take pictures of bones and other body tissues.

• Ultrasound (sonography). This test uses sound waves and a computer to create images.

• Lymph node biopsy. A sample of tissue is taken from the lymph nodes. It’s checked with a microscope for cancer cells.

• Lumbar puncture. A special needle is placed into the lower back, into the spinal canal. This is the area around the spinal cord. This is done to check the brain and spinal cord for cancer cells. A small amount of cerebral spinal fluid (CSF) is removed and sent for testing. CSF is the fluid around the brain and spinal cord.

How is leukemia treated in children?

Your child may first need to be treated for low blood counts, bleeding, or infections. Your child may receive:

• Blood growth factors to increase the production of blood cells in the bone marrow

• Blood transfusion with red blood cells for low blood counts

• Blood transfusion with platelets to help stop bleeding

• Antibiotic medicine to treat any infections

Treatment will depend on the stage and other factors. Leukemia can be treated with any of the below:

• Chemotherapy. These are medicines that kill cancer cells or stop them from growing. They may be given into the vein (IV) or spinal canal, injected into a muscle, or taken by mouth. Chemotherapy is the main treatment for leukemia in children. Several medicines are often given at different times. It’s usually done in cycles, with rest periods in between. This gives your child time to recover from the side effects.

• Radiation therapy. These are high-energy X-rays or other types of radiation. They are used to kill cancer cells or stop them from growing. Radiation may be used in certain cases.

• High-dose chemotherapy with a stem cell transplant. Young blood cells (stem cells) are taken from the child or from someone else. This is followed by a large amount of chemotherapy medicine. This causes damage to the bone marrow. After the chemotherapy, the stem cells are replaced.

• Targeted therapy. These medicines may work when chemotherapy doesn’t. For example, it may be used to treat children with chronic myeloid leukemia (CML). Targeted therapy often has less severe side effects.

• Supportive care. Treatment can cause side effects. Medicines and other treatments can be used for pain, fever, infection, and nausea and vomiting

• Clinical trials. Ask your child's healthcare provider if there are any treatments being tested that may work well for your child. 

There are 3 stages in the treatment of acute leukemia. They include:

• Induction. This is a combination of chemotherapy and radiation. It’s done to stop the bone marrow from making abnormal cells. The goal is to no longer being able to detect cancer cells. This is called remission. Your child may be in the hospital for long periods of time. He or she will also have frequent visits to the oncologist.

• Intensification. This is also called consolidation. This is ongoing chemotherapy treatment for about 1 to 2 months. This is done even when leukemia cells are not found. 

• Maintenance. This is smaller doses of chemotherapy for a longer period of time. It can last from months to years. Your child may also have periods of chemotherapy at higher doses during this time.

The bone marrow can start making abnormal cells again (relapse) during any stage of treatment. This can occur months or years after treatment has ended.

With any cancer, how well a child is expected to recover (prognosis) varies. Keep in mind:

• Getting medical treatment right away is important for the best prognosis. Cancer that has spread is harder to treat.

• Ongoing follow-up care during and after treatment is needed.

• New treatments are being tested to improve outcome and to lessen side effects.

What are possible complications of leukemia in a child?

A child may have complications from the tumor or from treatment. They may also be short-term or long-term.

Treatment may have many side effects. Some side effects may be minor. Some may be serious and even life-threatening. Your child may take medicines to help prevent or lessen side effects. You’ll be given instructions about what you can do at home.

Possible complications of leukemia can include:

• Serious infections

• Severe bleeding (hemorrhage)

• Thickened blood from large numbers of leukemia cells

Another possible complication is superior vena cava syndrome. The superior vena cava is the large blood vessel that supplies blood to the upper body. If your child has an enlarged thymus gland in the chest, it can press on the superior vena cava. It may cause very serious symptoms and be life-threatening.

Possible long-term complications from the leukemia or the treatment can include:

• Return of the leukemia

• Growth of other cancers

• Heart and lung problems

• Learning problems

• Slowed growth and development

• Problems with the ability to have children in the future

• Bone problems such as thinning of bones (osteoporosis)

What can I do to prevent leukemia in my child?

Most childhood cancers, including leukemia, can’t be prevented. The risk from X-rays and CT scans is very small. But healthcare providers advise against them in pregnant women and children unless absolutely needed.

How can I help my child live with leukemia?

A child with leukemia needs ongoing care. Your child will be seen by oncologists and other healthcare providers to treat any late effects of treatment and to watch for signs or symptoms of the cancer returning. Your child will be checked with imaging tests and other tests. And your child may see other healthcare providers for problems from the cancer or from treatment.

You can help your child manage his or her treatment in many ways. For example:

• Your child may have trouble eating. A dietitian may be able to help.

• Your child may be very tired. He or she will need to balance rest and activity. Encourage your child to get some exercise. This is good for overall health. And it may help to lessen tiredness.

• If your child smokes, help him or her quit. If your child doesn’t smoke, make sure he or she knows the danger of smoking.

• Get emotional support for your child. Find a counselor or child support group can help.

• Make sure your child attends all follow-up appointments.

When should I call my child’s healthcare provider?

Call the healthcare provider if your child has:

• Symptoms that get worse

• New symptoms

• Side effects from treatment

Key points about leukemia in children

• Leukemia is cancer of the blood. The cancer cells develop in the bone marrow and go into the blood. Other tissue and organs that may be affected include the lymph nodes, liver, spleen, thymus gland, brain, spinal cord, gums, and skin.

• When a child has leukemia, the bone marrow makes abnormal blood cells that do not mature. The abnormal cells are usually white blood cells (leukocytes). And with leukemia, the bone marrow makes fewer healthy cells. 

• Common symptoms of leukemia in children include feeling tired and weak, easy bruising or bleeding, and frequent or long-term infections.

• Leukemia is diagnosed with blood and bone marrow tests. Imaging may be done to look for signs of leukemia in different parts of the body.

• Chemotherapy is the main part of treatment leukemia in children.

• A child with leukemia may have complications from the leukemia and from the treatment.

• Ongoing follow-up care is needed during and after treatment.

Next steps

Tips to help you get the most from a visit to your child’s healthcare provider:

• Know the reason for the visit and what you want to happen.

• Before your visit, write down questions you want answered.

• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.

• Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.

• Ask if your child’s condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if your child does not take the medicine or have the test or procedure.

• If your child has a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice.