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Chronic myeloid leukemia (CML) is a cancer of the blood and bone marrow.
Leukemia occurs when the bone marrow makes too many cancer cells. These cells are called blasts. As blasts grow and divide rapidly, healthy blood cells cannot do their jobs. The blood does not function correctly. The patient cannot fight infection well.
CML is a chronic leukemia. It develops slowly over time. It may take weeks or months for symptoms to appear. Chronic also means that the leukemia may last a long time. Acute leukemias make children ill quickly.
CML is rare in children. Only 110–120 cases are seen each year in the United States and Canada.
About 90–95% of children with CML have a genetic change called the Philadelphia chromosome. The Philadelphia chromosome is not passed from parent to child. It occurs randomly.
Drugs called tyrosine kinase inhibitors (TKIs) are the first line of treatment. They target tyrosine kinase enzymes, which cause leukemia cells to grow and divide quickly.
CML develops slowly. Children with CML may not have symptoms at first.
Common CML symptoms include:
Tests to diagnose CML may include:
During the physical exam, the doctor will check general signs of health. The doctor will:
The doctor may conduct a nervous system exam to look at the function of the brain, spine, and nerves. Sometimes they will order diagnostic imaging tests. Diagnostic imaging tests make images of the body’s soft tissues, organs, and bones.
If tests indicate cancer, doctors will order more tests to find out the type of cancer.
CML has 3 phases. The phase depends on the number of leukemia (blast) cells in the blood and bone marrow.
Treatment depends on the phase of cancer.
First-line treatment for CML is usually the drug imatinib (Gleevec®). This drug is a type of targeted therapy known as tyrosine kinase inhibitor (TKI). Tyrosine kinase is a property of certain enzymes made by the body. The tyrosine kinase activity can become too high in cancer, causing cancer cells to grow. Imatinib blocks the tyrosine kinase activity and helps stop the growth of cancer cells.
During treatment, doctors closely watch how patients respond to therapy. This is called monitoring. Monitoring may include a health history, physical exam, complete blood count, and molecular testing.
Molecular testing can measure the number of leukemia cells in blood. It can find 1 leukemia cell among 10,000–100,000 normal cells. Molecular tests occur every 3–6 months after the start of therapy.
Testing can also show changes in CML cells. After taking a TKI drug, CML cells may change. The change may mean the medicine will not work as well. Doctors use this information to guide treatment.
Children may face side effects not seen in adults, such as growth problems. This is because children are growing during treatment with TKI drugs. Talk to your child’s care team about possible side effects.
A stem cell transplant (also known as bone marrow transplant or hematopoietic cell transplant) is another treatment option for CML.
A transplant can cure CML. But the patient must have a suitable cell donor.
A transplant can have serious side effects.
"I bungee jumped in New Zealand. I skydived in Montauk. I rock climbed and rappelled next to a waterfall. If I can beat cancer, there's nothing that I can't do." —Darshana Magan
Darshana Magan was diagnosed with an advanced stage of chronic myeloid leukemia when she was 11. Learn how she dealt with her fear of relapse and now advocates for her health as an adult childhood cancer survivor.
When discussing prognosis, doctors often talk about the 5-year survival rate. This rate is the percentage of patients who live at least 5 years after diagnosis.
For chronic leukemias, 5-year survival rates are less helpful. Children may live for a long time with their leukemia without being cured. Five-year survival rates for pediatric CML are 90% in the United States.
Patients may need to take TKI drugs to treat their CML for the rest of their lives. The long-term side effects of these drugs, such as effects on puberty and fertility, are not known. Researchers trying to find out if it is possible to stop taking TKI drugs or reduce their dosage.
Stem cell transplants can also have long-term side effects. These may include problems with growth, puberty, fertility, and organ function. Talk to your care team for more details.
It is important to have regular follow-up appointments. Patients should also have good health habits. These include eating healthy foods, doing regular physical activities, and getting enough sleep. Talk to your care team for more information.
Together does not endorse any branded product mentioned in this article.
Reviewed: August 2023