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300 Longwood Avenue
Boston, MA 02115
(617) 355-6000
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My Child Has:
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Juvenile Myelomonocytic Leukemia
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Leukemia is cancer of the blood. It develops in the bone marrow, the soft, spongy center of the long bones that produces the three major blood cells: white blood cells to fight infection; red blood cells that carry oxygen; and platelets that help blood clot and stop bleeding.
When a child has leukemia, the bone marrow, for an unknown reason, begins to make white blood cells that do not mature correctly, but continue to reproduce themselves. Normal, healthy cells only reproduce when there is enough space for them to fit. The body can regulate the production of cells by sending signals when to stop. With leukemia, these cells do not respond to the signals to stop and reproduce, regardless of space available.
These abnormal cells reproduce very quickly and do not function as healthy white blood cells to help fight infection. When the immature white blood cells, called blasts, begin to crowd out other healthy cells in the bone marrow, the child experiences the symptoms of leukemia (i.e., infections, anemia, bleeding).
JMML is, in some ways, similar to chronic myelogenous leukemia (CML), an uncommon leukemia in children. JMML is a leukemia in which the normal bone marrow production of cells becomes very disregulated. A preponderance of immature monoocytes, a type of white blood cell, are produced in the marrow. The marrow continues to produce these abnormal cells, which crowd out other healthy blood cells. JMML generally cause a more severe disruption in blood counts early in the disease than CML, and is not as responsive to treatment.
The symptoms associated with juvenile myelomoncytic leukemia can occur over a period of weeks to months.
As you read further below, you will find general information about JMML. If you would like to view summary information about cancer first, see the cancer overview.
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Leukemia is the most common form of cancer in childhood. It affects approximately 3,000 children each year in the US, accounting for about 30 percent of childhood cancers. Leukemia can occur at any age, although it is most commonly seen in children between 2 and 6 years of age. The disease occurs slightly more frequently in males than in females, and is more commonly seen in Caucasian children than in African-American children, or children of other races.
JMML usually affects children under the age of 2 years. It is a very rare form of childhood leukemia.
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The majority of childhood leukemias are acquired genetic diseases. This means that gene mutations and chromosome abnormalities in cells occur sporadically (by chance). The immune system plays an important role in protecting the body from diseases, and possibly cancer. An alteration or defect in the immune system may increase the risk for developing leukemia. Factors such as exposure to certain viruses, environmental factors, chemical exposures, and various infections have been associated with damage to the immune system.
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In addition to juvenile myelomonocytic leukemia (JMML), there are three other main types of leukemia in children:
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- acute lymphocytic leukemia (ALL) - also called lymphoblastic or lymphoid leukemia, accounts for about 75 to 80 percent of the childhood leukemias. In this form of the disease, the lymphocyte cell line is affected. The lymphocytes, a type of white blood cell, normally fight infection. With acute lymphocytic leukemia, the bone marrow makes too many immature lymphocytes (lymphoblasts) and they do not mature correctly. The lymphoblasts overproduce, thus crowding out other blood cells. In addition, these immature blood cells (lymphoblasts) do not work properly to fight infection. In some cases, these cancerous lymphocytes can be found in the fluid surrounding the brain and spinal cord as well as other organs.
- acute myelogenous leukemia (AML) - also called granulocytic, myelocytic, myeloblastic, or myeloid leukemia, accounts for about 20 percent of the childhood leukemias. Acute myelogenous leukemia is a cancer of the blood in which too many myeloblasts, a type of immature white blood cell, are produced in the marrow. With acute myelogenous leukemia, the bone marrow makes too many of these cells and they do not mature correctly. The myeloblasts overproduce, thus, crowding out other blood cells. In addition, these immature blood cells do not work properly to fight infection. AML cells are found in the blood and bone marrow. Occasionally they are also found in the fluid surrounding the brain and spinal cord. Rarely, AML tumor cells form into solid tumors called chloromas.
- chronic myelogenous leukemia (CML) - is uncommon in children. Chronic myelogenous leukemia is cancer of the blood in which too many immature white blood cells are produced in the marrow. With this disease, the bone marrow makes too many of these cells and they do not mature correctly. The marrow continues to produce these abnormal cells, which crowd out other healthy blood cells. Chronic myelogenous leukemia can occur over a period of months or years. A specific chromosome rearrangement is found in patients with CML. Part of chromosome #9 breaks off and attaches itself to chromosome #22, so that there is an exchange of genetic material between these two chromosomes. This rearrangement changes the position and functions of certain genes, which results in uncontrolled cell growth. Other chromosome abnormalities can also be present.
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Because leukemia is cancer of the blood-forming tissue called the bone marrow, the initial symptoms are often related to irregular bone marrow function. The bone marrow is responsible for producing the body's blood cells, including the red blood cells, white blood cells, and platelets.
With JMML, there are usually no symptoms in the early stages. When then do occur, your child may experience symptoms over a period of weeks or months.
When leukemia occurs, the abnormal white blood cells (blasts) begin to reproduce very rapidly and begin crowding out and competing for nutrients and space with the other healthy cells. The following are the most common symptoms of leukemia. However, each child may experience symptoms differently. Symptoms may include:
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- general feeling of fatigue
- recurrent infections - although there may be an unusually high number of white blood cells on a blood count of a child with leukemia, these white blood cells are immature and do not fight infection. The child may have had repetitive viral or bacterial infections over the past few weeks.
- bone and joint pain - pain in bones and joints is another common symptom of leukemia. This pain is usually a result of the bone marrow being overcrowded and "full."
- abdominal distress - abdominal pain may also be a symptom of leukemia. Leukemia cells can collect in the kidney, liver, and spleen, causing enlargement of these organs. Pain in the abdomen may cause a child to have loss of appetite and weight loss.
- swollen lymph nodes - the child may also have swelling in the lymph nodes under the arms, in the groin, chest, and in the neck. Lymph nodes are responsible for filtering the blood. Leukemia cells may collect in the nodes, causing swelling.
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It is important to understand that the symptoms of leukemia may resemble other blood disorders or medical problems. These are common symptoms of the disease, but do not include all possible symptoms. Children may experience symptoms differently. Always consult your child's physician when you have a concern.
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In addition to a complete medical history and physical examination, diagnostic procedures for leukemia may include:
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- bone marrow aspiration and biopsy - marrow may be removed by aspiration or a needle biopsy under local anesthesia. In aspiration biopsy, a fluid specimen is removed from the bone marrow. In a needle biopsy, a core sample of bone and bone marrow is removed. These methods are often used together.
- complete blood count (CBC) - a measurement of size, number, and maturity of different blood cells in blood
- additional blood tests - may include blood chemistries, evaluation of liver and kidney functions, and genetic studies
- chromosomal analysis - additional tests that can help distinguish JMML from other leukemias and help physicians tailor treatment to the specific disease
- lymph node biopsy - surgical removal of lymph node tissue to examine under a microscope to look for the presence of cancer cells
- spinal tap/lumbar puncture - a special needle is placed into the lower back, into the spinal canal. This is the area around the spinal cord. Cerebral spinal fluid (CSF) is the fluid that bathes your child's brain and spinal cord. A small amount of (CSF) can be removed and sent for testing to determine if there are leukemia cells present.
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Specific treatment for leukemia will be determined by your child's physician based on:
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- your child's age, overall health, and medical history
- your child's tolerance for certain medications, procedures, or therapies
- your opinion or preference
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Treatment usually begins by addressing the presenting symptoms such as anemia, bleeding, and/or infection. In addition, treatment for leukemia may include (alone or in combination) the following:
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- chemotherapy - for JMML, chemotherapy is not generally a successful treatment, however, it may be used to keep the leukemia under control while the patient is prepared for a stem cell transplant.
Chemotherapy is a drug treatment that works by interfering with the cancer cell's ability to grow or reproduce. Different groups of drugs work in different ways to fight cancer cells and shrink tumors. Chemotherapy may be used alone for some types of cancer or in conjunction with other therapy such as radiation. Often, a combination of chemotherapy drugs is used to fight a specific cancer. Certain chemotherapy drugs may be given in a specific order depending on the type of cancer it is being used to treat. While chemotherapy can be quite effective in treating certain cancers, the agents do not differentiate normal healthy cells from cancer cells. Because of this, there can be many adverse side effects during treatment. Being able to anticipate these side effects can help the care team, parents, and child prepare, and, in some cases, prevent these symptoms from occurring, if possible.
Chemotherapy is systemic treatment, meaning it is introduced to the bloodstream and travels throughout the body to kill cancer cells. Chemotherapy can be given:
- as an injection into the muscle or fat tissue
- intravenously (directly to the bloodstream; also called IV)
- intrathecally - chemotherapy given directly into the spinal column with a needle
- stem cell transplant - stem cell transplantation offers the best option for overcoming JMML. This treatment involves stem cells, a specific type of cell from which all blood cells develop. Stem cells develop into red blood cells to carry oxygen, white blood cells to fight disease and infection, and platelets to aid in blood clotting. Stem cells are found primarily in the bone marrow, but some also circulate in the blood stream.
Treatment begins with high-dose chemotherapy (perhaps combined with radiation therapy) to destroy all of the bone marrow, stem cells and cancerous cells, in the body. Then, healthy stem cells from another person is used to help restore normal blood production in the patient with JMML. The use of stem cells from another individual whose tissue is the same as, or almost the same as, the patient's is called allogeneic transplantation.
- biological therapy - a wide range of substances that may be able to involve the body's own immune system to fight cancer or lessen harmful side effects of some treatments
- other medications - to prevent or treat damage to other systems of the body caused by leukemia treatment, for example, prevention and treatment of chemotherapy-related nausea
- blood transfusions - red blood cells, platelets
- antibiotics - to prevent/treat infections
- continuous follow-up care - to determine response to treatment, detect recurrent disease, and manage late effects of treatment
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JMML does not have the three phases (chronic phase, acclerated phase and blast crisis) that are common in CML.
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Prognosis greatly depends on:
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- disease response to treatment.
- age and overall health of the child.
- your child's tolerance of specific medications, procedures, or therapies.
- new developments in treatment.
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As with any cancer, prognosis and long-term survival can vary greatly from child to child. Prompt medical attention and aggressive therapy are important for the best prognosis. Continuous follow-up care is essential for the child diagnosed with leukemia. Side effects of radiation and chemotherapy, as well as second malignancies, can occur in survivors of leukemia. New methods are continually being discovered to improve treatment and to decrease side effects of the treatment for the disease.
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In the area of stem cell transplantation, the Dana-Farber/Children's Transplant Program is one of only eight institutions around the country that are investigating the use of umbilical cord transplantation. Also under study is a novel method for preventing graft versus host disease, a serious complication that occurs when transplanted cells do not recognize the tissues and organs of the recipient's body and react against the recipient's tissue. The result of this treatment approach, if it continues to be as successful, will be that the degree of match between donor and the recipient will not need to be particularly close, greatly increasing the pool of potential donors for each patient. This could also eliminate the need for long-term drug therapy traditionally needed to treat graft versus host disease.
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The information on this website should not be taken as medical advice,
which can only be given to you by your personal health care professional. |
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Copyright © Children's Hospital Boston. All rights reserved. |
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