Understanding Chronic Myeloid Leukemia in Children

Each year, approximately 150 children in the United States are diagnosed with chronic myeloid leukemia. Although rare in children and teens, about 2 to 3 percent of leukemias diagnosed in children under 15 and 9 percent in teens 15 to 19 years of age are myeloid leukemia.

Early symptoms of the disease can develop slowly, making a quick diagnosis difficult.

Here’s more about it:

how to recognize the signs of CML in children what treatments are effective against the disease when to see your doctor if you suspect your child is ill

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

Chronic myeloid leukemia, also called chronic myeloid 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 numerous health problems.

There are three stages of CML:

The chronic phase. This phase can last for months or years, with or without significant symptoms. At this point, a blood test can show abnormal blood cells and blood cell counts — usually less than 10 percent leukemia, or “blast cells.”The accelerated phase. This phase marks an increase, usually 10 to 19 percent, in the number of blast cells produced in the blood and bone marrow. The explosion phase. Also referred to as the ‘explosion crisis’, this phase is the most advanced phase of CML. At present, more than 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. In particular, 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 faster than regular blood cells.

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

Again, it can take months or years for CML to make progress. As a result, symptoms can be difficult to spot in the early stages and can also vary significantly from child to child. The symptoms may also be related to the stage of cancer a child is in.

Symptoms in the chronic phase:

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

Accelerated or blast phase symptoms:

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

Different from mature CML

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

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

Blood Test. A complete blood count (CBC) can help identify blood cell counts and whether they are irregular.Bone marrow aspiration/biopsy. In a bone marrow biopsy, bone marrow fluid or tissue can be extracted from the hip bones via aspiration or biopsy for examination in a laboratory. 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 help diagnose 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 in 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 begins in childhood. It is essential to closely monitor a child with CML. Cancer treatment during key periods, such as puberty, can affect 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 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, TKI therapy eliminates enough cancer cells for healthy cells to take their place.

The goal of treatment is remission, which happens when cancer cells are no longer detected in the body. TKI therapy can 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 known as a bone marrow transplant. Your doctor may go down this road if cancer progresses despite TKI therapy and other medications.

In this procedure, your child will receive an infusion of healthy stem cells from a donor (possibly a relative) that will allow the body to produce healthy white blood cells, red blood cells, and platelets.

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

Read this to learn more 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 related to diet, exposure to chemicals, certain infections or exposure to smoke. Genetics isn’t a risk factor either — so if someone in your family had CML, it’s not necessarily likely to be passed on or in another child.

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

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

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

However, researchers note that this statistic is not very helpful, as a child can have this cancer for months or years without realizing it.

The good news is that survival rates increase as new drugs and targeted therapies are used to manage the disease.

CML is very rare in children. Researchers aren’t sure what causes it, and the chronic nature of the disease means it can take longer to diagnose and longer to treat. If your child shows any signs of concern, talk to your pediatrician.

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