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Health Tips
Childhood Leukemia
Key Statistics About Childhood Leukemia
American Cancer Society
Leukemia is the most common cancer in children and adolescents. It accounts for almost 1/3 of all cancers in children under age 15 and 1/4 of cancers occurring before age 20. The American Cancer Society predicts that about 2,700 children will be diagnosed with leukemia in the United States during the year 2002.
Of the 2,700 children with leukemia, about 2,000 will be diagnosed with ALL. Many of the remaining children will be diagnosed with AML. Chronic leukemias are very rare in children. ALL is most common in early childhood, peaking between ages 2 and 3 years of age. AML is most common during the first 2 years of life and is less common among older children. AML cases start to increase again during the teenage years, with AML becoming the most common acute leukemia in adults over 55 years of age. ALL is slightly more common among white children than among African-American and Asian-American children, and is more common in boys than in girls. AML is equally rare among boys and girls of all races.
What is Leukemia?
National Cancer Institute
Leukemia is a type of cancer. Cancer is a group of more than 100 diseases that have two important things in common. One is that certain cells in the body become abnormal. Another is that the body keeps producing large numbers of these abnormal cells.
Leukemia is cancer of the blood cells. To understand leukemia, it is helpful to know about normal blood cells and what happens to them when leukemia develops
Normal Blood Cells
National Cancer Institute
The blood is made up of fluid called plasma and three types of cells. Each type has special functions.
- White blood cells (also called WBCs or leukocytes) help the body fight infections and other diseases.
- Red blood cells (also called RBCs or erythrocytes) carry oxygen from the lungs to the body's tissues and take carbon dioxide from the tissues back to the lungs. The red blood cells give blood its color.
- Platelets (also called thrombocytes) help form blood clots that control bleeding.
Blood cells are formed in the bone marrow, the soft, spongy center of bones. New (immature) blood cells are called blasts. Some blasts stay in the marrow to mature. Some travel to other parts of the body to mature.
Normally, blood cells are produced in an orderly, controlled way, as the body needs them. This process helps keep us healthy.
Leukemia Cells
National Cancer Institute
When leukemia develops, the body produces large numbers of abnormal blood cells. In most types of leukemia, the abnormal cells are white blood cells. The leukemia cells usually look different from normal blood cells, and they do not function properly.
Types of Leukemia
National Cancer Institute
There are several types of leukemia. They are grouped in two ways. One way is by how quickly the disease develops and gets worse. The other way is by the type of blood cell that is affected.
Leukemia is either acute or chronic. In acute leukemia, the abnormal blood cells are blasts that remain very immature and cannot carry out their normal functions. The number of blasts increases rapidly, and the disease gets worse quickly. In chronic leukemia, some blast cells are present, but in general, these cells are more mature and can carry out some of their normal functions. Also, the number of blasts increases less rapidly than in acute leukemia. As a result, chronic leukemia gets worse gradually.
Leukemia can arise in either of the two main types of white blood cells - lymphoid cells or myeloid cells. When leukemia affects lymphoid cells, it is called lymphonic leukemia. When myeloid cells are affected, the disease is called myeloid or myelogenous leukemia.
These are the most common types of leukemia:
- Acute lymphocytic leukemia (ALL) is the most common type of leukemia in young children. This disease also affects adults, especially those age 65 and older.
- Acute myeloid leukemia (AML) occurs in both adults and children. This type of leukemia is sometimes called acute nonlymphocytic leukemia (ANLL).
- Chronic lymphocytic leukemia (CLL) most often affects adults over the age of 55. It sometimes occurs in younger adults, but it almost never affects children.
- Chronic myeloid leukemia (CML) occurs mainly in adults. A very small number of children also develop this disease.
Hairy cell leukemia is an uncommon type of chronic leukemia.
Leukemia Symptoms
National Cancer Institute
Leukemia cells are abnormal cells that cannot do what normal blood cells do. They cannot help the body fight infections. For this reason, people with leukemia often get infections and have fevers.
Also, people with leukemia often have less than the normal amount of healthy red blood cells and platelets. As a result, there are not enough red blood cells to carry oxygen through the body. With this condition, called anemia, patients may look pale and feel weak and tired. When there are not enough platelets, patients bleed and bruise easily.
Like all blood cells, leukemia cells travel through the body. Depending on the number of abnormal cells and where these cells collect, patients with leukemia may have a number of symptoms.
In acute leukemia, symptoms appear and get worse quickly. People with this disease go to their doctor because they feel sick. In chronic leukemia, symptoms may not appear for a long time; when symptoms do appear, they generally are mild at first and get worse gradually. Doctors often find chronic leukemia during a routine checkup -- before there are any symptoms.
These are some of the common symptoms of leukemia:
- Fever, chills, and other flu-like symptoms
- Weakness and fatigue
- Frequent infections
- Loss of appetite and/or weight
- Swollen or tender lymph nodes, liver, or spleen
- Easy bleeding or bruising
- Tiny red spots (called petechiae) under the skin
- Swollen or bleeding gums
- Sweating, especially at night
- Bone or joint pain
In acute leukemia, the abnormal cells may collect in the brain or spinal cord (also called the central nervous system or CNS). The result may be headaches, vomiting, confusion, loss of muscle control, and seizures. Leukemia cells also can collect in the testicles and cause swelling. Also, some patients develop sores in the eyes or on the skin. Leukemia also can affect the digestive tract, kidneys, lungs, or other parts of the body.
In chronic leukemia, the abnormal blood cells may gradually collect in various parts of the body. Chronic leukemia may affect the skin, central nervous system, digestive tract, kidneys, and testicles.
Can Leukemia Be Prevented?
American Cancer Society
Right now there is no known way to prevent most cases of leukemia. Unlike some other types of cancer, most leukemia is not linked to lifestyle risk factors. Children with a higher risk of leukemia (such as those who have Li Fraumeni syndrome or Down's syndrome) should have careful medical exams by their doctor. For some people, treatment with chemotherapy or radiation for other, earlier cancers may cause secondary (post-treatment) leukemias.
But again, the cause of most cases of leukemia is not known. Parents of children with leukemia need to remember that there is nothing they could have done to prevent this illness.
Childhood Leukemia Risk Factors
American Cancer Society
As leukemia treatment has improved over the past 20 years, research has focused on why some children have a better chance of cure than others do. Certain features were found among children with good or poor responses to treatment. These are called prognostic features, meaning they help predict the course of the disease. These features are used to help doctors decide what type of treatment is best for a given patient.
Nearly all cases of childhood leukemia are of the acute type: ALL or AML. Children with leukemia are divided into two groups: low-risk and high-risk. The high-risk group is given more intensive treatment.
Following are some of the prognostic features used in ALL to separate the two groups:
- Age: children younger than 1 to 2 years and children older than 10 years are higher risk patients
- White Blood Cell Count: children with white cell counts greater than 50,000 per cubic millimeter when the leukemia is found usually do worse with standard treatment
- Cytogenetics (study of chromosomes): certain features of chromosomes can indicate higher or lower risk
- Sex: girls have a greater chance of cure compared to boys
- Race: ALL in African Americans tends to respond less well to treatment than it does in children of other races
- Central Nervous System Disease: Involvement of the central nervous system usually means a worse response to treatment
- Response to treatment: Children who have a good response to treatment in the first week or two usually do better in the long run
For AML, these are some of the prognostic features:
- White Blood Cell Count: Patients with a white cell count greater than 100,000 per cubic millimeter do worse with standard treatment
- Cytogenetics: Certain features of chromosomes can indicate higher or lower risk
- Morphology (form/appearance): Certain features of cells indicate a worse outlook
- Down's Syndrome: Children with Down's syndrome have a higher cure rate compared to those without this condition
- Response to Treatment: Children who respond after the first course of chemotherapy generally do better in the long run
What Should You Ask your Doctor About Childhood Leukemia?
American Cancer Society
It is important to have honest, open communication with your doctor about your child's condition. Your doctor and the rest of the cancer care team want to answer all of your questions. For instance, consider these questions:
- Exactly what kind of leukemia does my child have? (You could ask your doctor to write this down for you)
- What are the prognostic features?
- What are the treatment choices?
- What do you recommend, and why?
- What side effects are there to the treatments that you recommend?
- What is my child's outlook for survival?
- What can be done to help reduce the side effects from the chemotherapy?
- What are the chances that the leukemia will come back once my child is in remission?
Be sure to add your own questions to this list.
How is Childhood Leukemia Treated?
American Cancer Society
As noted earlier, leukemia is not a single disease. It is really a group of diseases, and treatment options for each child are based on the type of leukemia, its stage, and certain prognostic features.
It is important to make sure that your child's treatment reflects his or her risk group as described earlier. Your child should be treated according to a set of instructions called a protocol from the National Cancer Institute or a cooperative study group.
This section provides general information about treatments for the two main types of childhood leukemia. Keep in mind, though, that every person is unique, and treatment decisions for each child will be made based on a number of individual factors.
Chemotherapy
Chemotherapy refers to the use of drugs to kill cancer cells. Usually the drugs are given into a vein or by mouth. Once the drugs enter the bloodstream, they spread throughout the body. Chemotherapy is the main treatment for nearly all types of leukemia. In general, ANLL treatment will involve higher doses of chemotherapy over a shorter period of time, and ALL will use lower doses over a longer period of time.
While chemotherapy drugs kill cancer cells, they can also damage normal cells. This happens because they target rapidly growing cells such as cancer cells, but in the process they also damage other fast growing cells.
The lining of the mouth and intestines, hair follicles, and blood cells all grow rapidly and are likely to be affected by chemotherapy.
As a result, children being treated with chemotherapy may have a higher risk of infection (from low white blood cell counts), may bruise or bleed easily (from low blood platelets), and tire easily (from low red blood cell counts). Other side effects of chemotherapy can include temporary hair loss, nausea, vomiting, and loss of appetite.
These side effects usually go away shortly after treatment ends. And there are often ways to manage these side effects during treatment. For example, there are drugs that can be taken along with the chemotherapy to prevent or reduce nausea and vomiting. Drugs know as growth factors are sometimes given to keep blood counts higher and reduce the chance of infection.
Other ways to reduce the risk of infection are by avoiding exposure to germs as much as possible by carefully washing hands and not eating uncooked fruits and vegetables. Children in treatment should also avoid large crowds and people who are sick.
During treatment, children might also receive antibiotics as added protection. They might start taking these at the first sign of infection, or even earlier as a preventive measure. If platelet counts are low, they might receive platelet transfusions and red blood cell transfusions if low red cell counts are causing shortness of breath or fatigue.
Tumor lysis syndrome is a side effect caused by the rapid breakdown of leukemia cells. When these cells are killed, they release substances into the bloodstream that can affect the kidneys, heart, and nervous system. Giving the child extra fluids or certain drugs that help rid the body of these toxins can prevent this problem.
Organs that could be damaged by chemotherapy include the kidneys, liver, testes, ovaries, brain, heart, and lungs. With careful monitoring, such side effects are rare.
One of the most serious side effects of ALL treatment is the chance of the child's developing a second leukemia, acute myelogenous leukemia. This happens in a small number of children after they have been given certain types of chemotherapy drugs. This risk must be balanced against the clear benefit of treating a life threatening disease such as leukemia with chemotherapy.
Treatment of ALL
For ALL, chemotherapy treatments are given in phases. Children with ALL are divided into high-risk and low-risk groups to make sure the correct types and doses of drugs are given.
Induction: In general, the purpose of the first phase, called induction, is to destroy as many cancer cells as quickly as possible. The child is in remission when cancer cells are no longer found in the bone marrow and the blood counts are normal. Until normal counts return, the child's condition is considered critical. More than 95% of children with ALL will enter remission after one month of treatment.
During induction, frequent trips to the doctor will be needed. Some children will need to receive spinal taps to instill chemotherapy into the cerebrospinal fluid in order to prevent cancer spreading to the central nervous system. And some (those with T-cell leukemia, high white blood counts or with cancer cells in the cerebrospinal fluid) will need radiation to the head as well.
Remission means that about 99% of the cancer cells have been killed; but there are still some leukemia cells in the body. That's why further phases of treatment are needed.
Consolidation: this goal of this phase, also called intensification, is to get rid of leukemia cells from places where they can "hide." This phase lasts 4-8 months. Several drugs are used in combination, depending on the child's risk category.
Maintenance: once the number of leukemia cells has been reduced by the first two phases of treatment, this last phase can begin. The total length of therapy for all three phases is 2 to 3 years for most children with ALL.
Treatment of AML
Induction/intensification: treatment for AML uses 2-3 different drugs at high doses, every 4 weeks for 6-8 months. Induction and intensification are very much alike. Maintenance chemotherapy is not needed in AML. Intrathecal chemotherapy is important and is given every 1-2 months.
Because the chemotherapy drugs needed to bring about remission in children with AML are so intensive, supportive care (nursing care, nutrition, antibiotic use, etc.) is especially important.
Stem Cell Transplantation (SCT)
This treatment can be used for children whose chances of survival are very poor. It can be done as soon a remission is achieved or if the child has a relapse during or shortly after treatment. It is not clear how useful it is for children whose relapse happens more than 6 months after the end of their initial treatment.
As noted earlier, chemotherapy can harm normal cells as well as cancer cells. Stem cell transplantation offers a way for doctors to use the high doses of chemotherapy needed for effective treatment. Although the drugs destroy the bone marrow, transplanted stem cells can restore the blood-producing bone marrow stem cells. Here's how it works.
Stem cells for transplantation are collected from the bone marrow or from the bloodstream (in a process called apheresis). These stem cells can come from either the child or, in most cases of leukemia, from a suitable donor.
The child is then given very high doses of chemotherapy to kill the cancer cells. After therapy, the stored stem cells are given to the patient as a blood transfusion. Then the waiting period begins as the stem cells settle in the child's bone marrow and start to grow and produce blood cells. Stem cell transplantation is still a fairly new and complex treatment. If the doctors think that a child with leukemia might be helped by this treatment, it is important that it be done at a hospital where the staff has experience with the procedure. Some transplant programs may not have experience in certain transplants, especially those from unrelated donors.
Stem cell transplantation is very expensive and requires a lengthy hospital stay. Because some insurance companies see it as an experimental treatment, they might not pay for it.
Radiation Therapy
For children with acute leukemia, radiation might be used to treat cancer that has spread to the central nervous system or testicles. It can also be used, though rarely, in an emergency to treat pressure on the windpipe. Even here it is being replaced by chemotherapy.
Surgery
Unlike most other cancers, surgery is not generally used to treat leukemia. This is because leukemia is a disease of blood and bone marrow and it is not possible to bring about a cure with surgery.
Surgery, however, may be used to help deliver treatment. A plastic tube can be surgically placed into a large vein. The tube, called a venous access device, allows chemotherapy drugs or other medicines to be given and blood samples removed without the need for repeated needle sticks.
What Happens After Treatment For Childhood Leukemia?
American Cancer Society
Follow-up exams are needed for several years after the treatment for leukemia is finished. These follow-up visits are very important. The doctor will continue to watch for signs that the cancer has come back, as well as for short-term and long-term side effects of treatment. Be sure to report any new symptoms to the doctor right away, so that relapse or side effects can be treated.
Checkups for children with leukemia involve careful physical exams, lab tests, and sometimes, x-rays. These checkups will usually be monthly during the first year, every other month the second year, every third month during the third year, and every 6 months until 5 years after treatment. After that time, it's a good idea to have the child see the doctor yearly for a checkup.
If the leukemia returns, it usually happens while the child is on treatment or right after treatment ends. It's unusual for high-risk ALL or AML to come back if there are no signs of the disease within two years after treatment ends.
For children who have had leukemia, possible long-term complications of treatment include damage to the heart, poor school performance, the chance of developing a second cancer, and problems with the ability to have children later in life.
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