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Around 150 children in the United States are diagnosed with chronic myeloid leukemia each year. While rare in kids and teenagers, approximately 2 to 3 percent of leukemia diagnosed in children under 15 years old and 9 percent in teens ages 15 to 19 is myeloid leukemia.

Early symptoms of the disease can be slow to develop, making a quick diagnosis difficult.

Here’s more about:

  • how to spot the signs of CML in children
  • what treatments are effective against the disease
  • when you should see your doctor if you suspect your child may be sick

Simply put, leukemia is cancer of the blood and bone marrow.

Chronic myeloid leukemia, also referred to as chronic myelogenous leukemia or CML, causes the body to produce too many immature white blood cells in the bone marrow — the spongy center of bones. Over time, these irregular cells take over the healthy cells and cause a host of health issues.

There are three phases of CML:

  • The chronic phase. This stage may last for months or years with or without any notable symptoms. At this time, a blood test might show abnormal blood cells and numbers of blood cells — usually fewer than 10 percent leukemia or “blast” cells.
  • The accelerated phase. This stage marks an increase, usually 10 to 19 percent, in the number of blast cells that are being produced in the blood and bone marrow.
  • The blast phase. Also called the “blast crisis,” this stage is the most advanced stage of CML. At this point, over 20 percent of cells in the bone marrow are irregular blast cells.

Genetic causes

CML is caused by a change in a person’s genes. Specifically, it almost always happens when the genes BCR (gene 9) and ABL1 (gene 22) exchange material, creating a genetic change called BCR-ABL1, or the Philadelphia chromosome (Ph). Blood cells that have the Ph translocation produce much more quickly than regular blood cells.

This mutation is not inherited, so it is not passed from a parent to a child in reproduction. Instead, researchers do not know exactly what causes the genetic change, and it’s possible that it just happens “by chance” in many cases.

Again, CML can take months or years to progress. As a result, symptoms in the early stages may be difficult to spot, and they may also vary considerably from one child to the next. The symptoms may also relate to the phase of cancer a child is in.

Chronic phase symptoms:

  • weakness
  • fatigue
  • fever
  • night sweats
  • pain in the abdomen (from the enlargement of the liver and/or spleen)
  • loss of appetite and/or weight loss
  • infections that do not go away easily or that recur

Accelerated or blast phase symptoms:

  • increase in bleeding or bruising
  • anemia
  • pain in the bones and joints
  • worsening infections
  • swollen lymph nodes in the arms, groin, chest, or neck

Different from adult CML

CML is much more common in adults than it is in children. While the signs and symptoms may be similar, CML tends to be more aggressive in children than it is in adults. For instance, CML in kids may have a higher risk of progressing beyond the chronic stage and into the accelerated and blast stages.

Your child’s pediatrician will take into consideration their symptoms and medical history before proceeding with further testing for CML. After a physical exam, your doctor may order the following tests to aid with diagnosis.

  • Blood test. A complete blood count (CBC) can help identify the number of blood cells and whether they’re irregular.
  • Bone marrow aspiration/biopsy. In a bone marrow biopsy, bone marrow fluid or tissue can be taken from the hip bones via aspiration or biopsy for examination in a lab. Doctors will look at the blood cells, their number and size, as well as whether the cells are mature or irregular.
  • Imaging tests. Your doctor may order an X-ray, MRI, or CT scan to aid with diagnosis and visualize how the cancer has affected the internal organs.
  • Other tests. There are also other tests that can look at your child’s chromosomes and any changes to the genes.

Treatments for children with CML are generally modeled after treatments used for adults; however, there is no specific protocol for treating CML that starts in childhood. It’s essential to monitor a child with CML closely. Cancer treatment during key periods, like puberty, may have an impact on growth, thyroid function, and more.

TKI therapy and chemotherapy

In the chronic phase, doctors give oral medications called tyrosine kinase inhibitors (TKI) to attack an enzyme of the same name, tyrosine kinase. This enzyme is what causes the cancer cells to grow and crowd out healthy cells.

Hydroxyurea, an oral chemotherapy drug, is generally the first drug doctors try along with TKI therapy. Together these treatments work to lower the number of white blood cells in the blood. Over time, the TKI therapy eliminates enough cancer cells so that healthy cells can take their place.

The treatment goal is remission, which happens when cancer cells are no longer detected in the body. TKI therapy may be used for years with monitoring of side effects and frequent testing of a child’s blood and bone marrow to assess how the treatment is working.

Stem cell transplant

A stem cell transplant is also called a bone marrow transplant. Your doctor may go this route if cancer progresses despite TKI therapy and other medications.

In this procedure, your child would receive an infusion of healthy stem cells from a donor (possibly a family member) that would allow the body to start producing healthy white blood cells, red blood cells, and platelets.

Stem cell transplants can carry some intense side effects, but they are also effective at fighting the disease in most cases.

Read this for more information about the possible side effects of CML treatment.

Researchers are still working to determine risk factors for CML in children. Currently, there are no proven factors involving diet, chemical exposure, certain infections, or exposure to smoke. Genetics are also not a risk factor — so if someone in your family had CML, it’s not necessarily likely that it will be passed down or occur in another child.

Things that may increase the chances of CML in some people include:

  • exposure to high doses of radiation (surviving a nuclear reactor accident, for example)
  • age (as children and adults get older, the risk goes up)
  • sex (males have a higher rate of CML than females, but researchers don’t know why)

It’s important to understand that CML is a lifelong cancer, so it is not fully curable. That said, the 5-year survival rate for children diagnosed with CML is between 60 and 80 percent and possibly as high as 90 percent.

However, researchers note that this statistic isn’t very helpful, as a child can have this form of cancer for months or years without realizing it.

The good news is that survival rates are increasing as new medications and targeted therapies are being used to manage the disease.

CML is very rare in kids. Researchers do not know exactly what causes it, and the chronic nature of the disease means it may take longer to diagnose and longer to treat. If your child is showing signs that concern you, contact your pediatrician.