Leukemia is a cancer of the white blood cells, which are the cells that help fight infection. The disease develops in the bone marrow. The bone marrow is the soft, spongy center of bones and is where blood cells are produced.

There are different kinds of leukemia. They are distinguished by how long it takes for the disease to progress (acute or chronic) and the type of white blood cell involved (lymphocyte or myelocyte). Leukemia is the most common form of childhood cancer.

Types of Leukemia

There are three main types of leukemia. They are categorized by how fast they develop and by the kind of white blood cell involved.

• Acute lymphocytic leukemia (ALL). It is also called lymphoblastic or lymphoid leukemia.
• Acute myeloid leukemia (AML). It is also called myelogenous, granulocytic, myelocytic, myeloid or myeloblastic leukemia
• Chronic myeloblastic leukemia (CML)

“Acute” means sudden − coming on in days or weeks.

“Chronic” means gradual − coming on over months or years.

Lymphocytes and myelocytes are two different kinds of white blood cell.

How Does Leukemia Develop?

When a child has leukemia, the bone marrow, for an unknown reason, begins to make faulty white blood cells. Normally, the body can regulate the production of cells by sending signals for when to stop producing more. Leukemia cells do not respond to the body’s signals. These cells go on reproducing themselves, even when there’s no more space in the bone marrow.

The bone marrow doesn’t just make infection fighting white blood cells. It also makes red blood cells and platelets. Red blood cells carry oxygen to all parts of the body. Platelets help with blood clotting to stop bleeding.

In leukemia, the abnormal white cells reproduce very quickly and do not fight infection well. These faulty white blood cells, called blasts, crowd the bone marrow. This can mean that not enough red blood cells or platelets are made. All this trouble in the bone marrow results in the symptoms of leukemia. These may include tiredness and problems with infections and bruising or bleeding. Bone pain can also occur as the bone marrow expands.

How Common Is Leukemia?

Leukemia is the most common form of cancer in childhood. It affects approximately 3,000 children each year in the United States. Leukemia accounts for about 30 percent of childhood cancers.

While leukemia can occur at any age, it is most commonly seen in children between 2 and 6 years old. The disease occurs slightly more often in males than in females. It is most commonly seen in Caucasian children.

What Causes Leukemia?

Most childhood leukemias are caused by chance mutations in the genes of white blood cells. Except for rare genetic cases, little is known about the causes of these diseases. Scientists are hard at work trying to learn how these mutations happen.

The immune system plays a key role in protecting the body from diseases. A fault in the immune system may increase the risk for getting leukemia. Things like getting certain viruses or other infections can lower immunity. Toxins in the environment or exposure to chemicals may also make the immune system weaker.

Associated Disorders / Conditions

Certain conditions may increase a child’s risk of developing leukemia.

• Down syndrome
• Fanconi anemia
• Neurofibromatosis
• Shwachman-Diamond syndrome
• Bloom syndrome
• Ataxia telangiectasia (Louis-Bar syndrome)
• Bone marrow disorders (myelodysplasia)
• Pre-birth X-ray exposure
• Significant radiation exposure
• Chemotherapy in the past
• Certain genetic conditions

What Are the Symptoms of Leukemia?

Leukemia is cancer of the bone marrow, where blood is formed. The early symptoms are often related to problems with the bone marrow.

While this list shows the common symptoms of leukemia, they are also common symptoms of other disorders. Always consult your child's doctor for a diagnosis.

• Anemia: Children may appear tired and pale, and may breathe faster to make up for the blood’s decreased ability to carry oxygen.
• Bleeding or bruising: Children may begin to bruise more easily. Tiny red dots (“petechiae”) are often seen on the skin. These are caused by very small blood vessels that have "leaked" or bled.
• Recurrent infections: The many white blood cells found in leukemia do not fight infection. The child may have had repeated viral or bacterial infections with a fever, runny nose and cough.
• Bone and joint pain: Pain from the pressure of the bone marrow being too crowded and “full” can mimic arthritis joint pain.
• Abdominal distress: Belly pain, poor appetite and / or weight loss may occur. Leukemia cells can collect in the kidney, liver, and spleen, causing swelling of these organs.
• Swollen lymph nodes: Lymph nodes under the arms or in the groin, chest or neck may swell. As they filter the blood, lymph nodes may collect leukemia cells.
• Difficulty breathing: In T-cell ALL, leukemia cells tend to clump around the thymus gland behind the breast bone. Wheezing, coughing, and / or painful breathing need prompt medical attention.

Diagnosis of Leukemia

In addition to a complete medical history and physical exam, a number of tests may be used for diagnosis. Some of these helps identify the exact type of cancer. Others are to find out whether the leukemia has invaded any specific organs of the body. All of this information is used to come up with the best treatment plan.

• Bone marrow aspiration and biopsy – A special hollow needle and general anesthesia are used. A bone marrow sample is removed and tested to find out the type of cancer.
• Complete blood count (CBC) – This test looks at the size, number, and stage of growth of different blood cells.
• Additional blood tests – These may include blood chemical levels, liver and kidney tests and genetic tests.
• Computerized tomography scan (CT or CAT scan) – X-rays and computer technology produce cross-section images (often called slices) of the body. CT scans are more detailed than general X-rays.
• Magnetic resonance imaging (MRI) – Large magnets, radio waves and a computer produce detailed images of body parts.
• X-ray – Invisible electromagnetic energy beams make a picture of tissues, bones and organs.
• Ultrasound (also called sonography) – High-frequency sound waves and a computer create images of blood vessels, tissues and organs.
• Lymph node biopsy – A small incision is made using local anesthetic. One or more lymph nodes are removed to be examined under a microscope.
• Spinal tap / lumbar puncture – general anesthesia is used. A special needle is placed into the spinal canal, below the level of the back where the spinal cord ends. The pressure is checked and a small amount of cerebral spinal fluid (CSF) is removed. This sample is tested for infection or other problems. CSF is the fluid that bathes your child's brain and spinal cord.

Stages

Unlike some other cancers, leukemia is not divided into stages. Instead, patients are assigned to risk groups depending on their age and the type of leukemia they have. Risk groups help determine treatment.

Treatment for Leukemia

Treatment for leukemia varies. Your child's doctor will decide what to do based on your child’s risk level. The risk level depends on:

• Your child's age
• Your child’s overall health and medical history
• Genetics
• The type of leukemia
• How well your child can tolerate the treatments
• How far along the disease is
• How the disease is expected to progress
• Your preference  

Treatment usually begins by taking care of the first symptoms. These are often anemia (too few red blood cells), bleeding and / or infection. Treatment for leukemia may also include:

• Chemotherapy – Strong medicines are given by mouth or through an IV (intravenously). These drugs target cells that are growing fast, as cancer cells do. Side effects are common because these strong drugs can also harm some normal cells.
• Intrathecal medications / chemotherapy – Medicine is given by needle into the area around the spinal cord.
• Radiation therapy – Targeted energy, such as X-rays, kills leukemia cells. It can help with pain from swollen liver, spleen or lymph nodes. It can also relieve pain from bone marrow expansion.
• Blood and bone marrow / stem cell transplantation – First, high-dose chemotherapy and maybe radiation are given to destroy the cancer cells in the bone marrow. Fresh, healthy stem cells are then needed to replace the bone marrow cells that have been killed. To do this, donor stem cells are given by IV. From the blood stream, they make their way to the bone marrow. These fresh stem cells then start making normal white blood cells, red blood cells and platelets.
• Biological / immunological therapy – Antibodies against the cancer cells are given. These may help the body’s immune system find and kill the bad cells. Or, they may help guide drugs or radiation directly to the cancer cells.
• Medicines – Drugs to prevent or treat side effects of leukemia treatment may be given. Medicines may also be given for nausea or pain.
• Blood transfusions – These may be used to replace red blood cells and / or platelets.
• Antibiotics – Medicines may be given to prevent or treat infections.
• Follow-up care – Follow-up is needed to gauge how well treatment is working. It can also help doctors know if the disease is coming back and help them manage any late effects of treatment.

What Are Clinical Trials?

Clinical trials are programs to test new therapies that may or may not turn out to be medical breakthroughs. Before being tested in humans, new drugs are tested thoroughly in the lab. A trial is the final step in deciding whether a new therapy is effective and safe in humans.

Research may look for better ways to target the disease more accurately. It also may look for new ways to use antibodies, and better stem cell transplant methods. 

Phases of Leukemia Treatment

There are various phases in the treatment of leukemia. These are:

Induction 

During the induction phase, chemotherapy and medications are given. Sometimes radiation is included, too.

The idea is to kill the leukemia cells in the blood as well as their parent cells in the bone marrow.

The goal of the induction phase is remission. “Remission” means the leukemia cells are no longer being made. The Induction phase may last about a month and can be repeated if the goal is not reached.

Consolidation / Intensification

Treatment is continued even though leukemia cells may not be visible. Though the leukemia cells may not be seen in a blood test or bone marrow examination, it is still possible that the cells are present in the body.

The goal of this phase is to kill off any remaining cancer cells.

Maintenance

During the maintenance phase, less intense chemotherapy is given over a long time. This phase can last months to several years.

The goal of this phase is to prevent a relapse.

Regular visits to your child's doctor are required. This is to make sure the treatment is working and to check for any recurrent disease. These visits are also needed to take care of any side effects of the treatment.

Relapsed, Refractory or Recurrent Leukemia

Relapse is when the bone marrow begins to make cancer cells again. There is no way to predict this. It can happen at any phase of treatment. It may also occur months or years after treatment has ended.

The expected outcome and treatment options after relapse depend on several things. One is the length of time between the diagnosis and when the leukemia comes back. The expected outcome and next steps also depend on where the leukemia reappears. Sometimes it is just seen in the bone marrow. However, it may come back in other parts of the body as well.

What Is the Outlook for a Child with Leukemia?

The prognosis for leukemia greatly depends on:

• How far the disease has spread
• The type of leukemia
• How well your child responds to treatment
• Genetics
• Age and overall health
• How well your child can tolerate the treatment
• New discoveries in treatment

The outlook and long-term survival are different for every cancer. Getting to a doctor and starting aggressive therapy quickly are key for the best outcome. A child with leukemia needs constant follow-up. Survivors can suffer from side effects of radiation and chemotherapy. Other cancers can occur as well. These may include skin, breast, brain / spine, thyroid gland, bone or other blood cancers. Monitoring for these diseases is crucial. Developing healthy habits like eating right and not smoking is important, too. New methods are being found every day to improve treatment and to decrease side effects from the treatment for this disease.

The term five-year survival rate means the percentage of patients who live at least five years after their cancer is diagnosed. With acute leukemias, these patients are probably cured. It is very rare for leukemia to return later than this. Current five-year survival rates are based on large numbers of children who were treated more than five years ago. These rates really can’t predict what will happen in your child’s case. Every child and every cancer are different. Also, because treatments change all the time, the survival rates from treatment done five or more years ago may not truly reflect today’s survival rates.

What Are the Long-Term Complications?

Childhood cancer and its treatment can create health problems later in life. This may mean a higher risk for heart, lung and kidney disease. It may also mean mental or emotional problems, issues with reproduction, or new cancers (See section on Outlook).

As they grow older, childhood cancer survivors can use help to stay on top of these risks. For this reason, 25 years ago, Cincinnati Children’s founded the first US Cancer Survivorship Program. This program gives medical care and mental and social support to childhood cancer survivors, into adulthood. Patients are welcome whether they were treated at Cincinnati Children’s or not.

Call Your Doctor If:

Caring for a youngster being treated for leukemia requires constant attention. Call 513-517-2234, 24 hours a day 7 days a week to be connected with a member of the team.

You should call your doctor, nurse or the oncologist on call immediately if your child, adolescent or young adult (has):

• A temperature greater than or equal to 100.4˚F (38˚C)
• A constant cough
• Any sign of infection
• A severe headache, sudden vomiting or change in level of alertness
• Pain in the rectal area
• Appears to have a hard, swollen stomach
• Experiences abdominal pain
• Bright red blood in stool or very dark, foul smelling stool
• Any change in normal bowel patterns, eating habits or appetite
• Diarrhea that lasts for one day or more
• Does not have a bowel movement in a day or two with prescribed medications for constipation
• Red or brown urine
• Urinates less than two times a day
• Becomes unable to eat or drink
• Drinks less fluid or vomits many times
• Continues to vomit even after receiving anti-nausea medication
• Blood in their vomit (consider the color of food eaten in the last 24 hours, such as red Jell-O or beets)
• Vomits green liquid
• Mouth pain so severe that they can neither sleep nor eat
• Excessive bleeding from mouth sores
• Continues to have a nosebleed after you have applied pressure for 10 minutes
• Cuts themselves and the bleeding does not stop after putting pressure over the site for 5 minutes
• An increase in bruising, red spots on the skin, increase in menstrual flow or blood in the urine

If your child has contact with anyone who is newly diagnosed with chickenpox or shingles, call the clinic / oncologist on call within 24 hours. Make sure their teacher(s) and school nurse notify you if your child has been exposed to these viruses.

Other reminders:

• Do not give your child aspirin, Tylenol (acetaminophen) or any over-the-counter medications unless prescribed by your doctor. (For example: cold medications such as Contac, vitamins, Advil or other products containing ibuprofen or acetaminophen). Patients with cancer may have lower numbers of platelets in the blood due to chemotherapy. Aspirin and ibuprofen affect how platelets work in the body and could increase the chance of bleeding. Tylenol (acetaminophen) could bring down a fever and cover up this sign of infection.
• Do not continue your child’s immunization program (baby shots) until you check with your doctor. Also, check with the doctor before other children in your family get their immunizations.
• Check with your primary oncologist before you take your child to the dentist. They may need to get antibiotics before dental work.
• Avoid crowds or persons who have colds or flu. We will let you know when you need to take extra precautions to protect your child from infection.
• Your child and members of your family and close contacts should receive the flu shot each season. Do not receive FluMist.