Leukemia in Children

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leukemia in children
Leukemia in Children

Leukemia is one of the most common types of cancer in children and young adults (1 in 3) Most childhood leukemias are acute lymphoblastic leukemia (ALL) and most of the remaining cases are acute myeloid leukemia (AML). Chronic leukemia is rare in children.

An overview of leukemia in children:

Cancer begins when cells in the body multiply out of control, which can happen almost anywhere in the body.

Leukemia is a cancer of cells that normally develop into several types of blood cells.

Leukemias often start with early forms of white blood cells, but some leukemias start in other types of blood cells.

Acute lymphoblastic leukemia (ALL): 3 out of 4 cases of pediatric leukemia are acute lymphoblastic leukemia. This leukemia begins in early forms of white blood cells called lymphocytes.

Acute myelogenous leukemia (AML): This type of leukemia accounts for most of the remaining cases of leukemia in children. AML starts from the myeloid cells which are usually white blood cells, red blood cells, and platelets.

Initiation and spread of leukemia:

Leukemia begins in the bone marrow, where leukemia cells form, crowding out normal cells, and most often leukemia cells leak into the bloodstream very quickly.

Some types of leukemia can spread to other parts of the body such as the lymph nodes, spleen, liver, central nervous system (brain and spinal cord), testicles, or other organs.

Risk Factors for Childhood Leukemia
Risk factors:
Little is known about the risk factors for childhood leukemia, and we can mention:

Genetic syndromes-
Genetic Syndromes:

Some genetic disorders can increase the risk of a child developing leukemia, including Down syndrome, as children with Down syndrome have a risk of developing acute lymphoblastic leukemia and acute myeloid leukemia several times higher than that of other children.

Inherited immune system problems.
Having a brother or sister with leukemia: Siblings (brothers and sisters) of children with leukemia have a slightly increased chance of developing leukemia but the risk is still low. The risk is much higher among twins (twins from one egg). If one twin is affected, the other has a 1 in 5 chance of developing leukemia as well. This risk is much higher if leukemia develops in the first year of life.
Having a parent who had leukemia as an adult does not appear to increase a child's risk of leukemia.
Environmental factors: such as radiation and some chemicals that increase the risk of developing diseases such as leukemia.
exposure to radiation:
Exposure to high levels of radiation is a risk factor for childhood leukemia as Japanese atomic bomb survivors had a higher risk of acute myeloid leukemia.

Radiation to the fetus during the first months of pregnancy may increase the risk of childhood leukemia, but the extent of this risk is not clear.

The potential risks of a fetus or baby being exposed to low levels of radiation (such as X-ray or CT scans) are not known with certainty. Some studies have found a small increase in risk while others have not found an increased risk, but for safety reasons, most doctors recommend that pregnant women and children not have the tests unless clearly needed.

Suppressing the immune system: Children who receive intensive treatment to suppress their immune system (especially children who have undergone organ transplants) have an increased risk of developing some types of cancer such as ALL and AML.
Exposure to chemotherapy and some other chemicals:
Children and adults who undergo chemotherapy for other cancers have a higher risk of developing a second cancer (usually AML) later in life.

Treatment with medications such as cyclophosphamide, doxorubicin, etoposide, and teniposide have been linked to an increased risk of leukemia. This leukemia usually develops within 5 to 10 years of treatment and tends to be difficult to treat.

Exposure to chemicals such as benzene (a solvent used in the cleaning industry and the manufacture of some drugs, plastics, and dyes) may cause acute leukemia in adults and rarely in children.
Several studies have found a possible link between childhood leukemia and household exposure to pesticides either during pregnancy or early childhood. Some studies have also found a potential increased risk among mothers who are exposed to these pesticides in the workplace before their child is born. However, most of these studies had limitations in the way they were conducted so more research is needed to try to confirm these results and provide more specific information about the potential risks.

What causes childhood leukemia?

The exact cause of most childhood leukemias is unknown as most children with leukemia do not have any known risk factors.

Detection and Diagnosis
Can childhood leukemia be detected early?

At this time there are no widely recommended blood tests or other tests for most children to look for leukemia before it begins to cause symptoms. Childhood leukemia is often found when a child has signs or symptoms that lead to a visit to the doctor and then the doctor orders blood tests that may indicate leukemia is the cause.

The best way to find this leukemia early is to pay attention to the possible signs and symptoms of this disease.

Signs and Symptoms of Childhood Leukemia.
Signs and symptoms of leukemia in children:
It should be noted that many of the symptoms that appear when developing leukemia appear when suffering from other diseases that are not related to cancer, but if the child suffers from any of them, he must visit the doctor for the necessary tests.

Leukemia begins in the bone marrow where new blood cells are made. Therefore, symptoms of leukemia occur due to problems in the bone marrow. As leukemia cells accumulate in the marrow, they crowd out normal cells and as a result, the child may not have enough normal red blood cells and blood cells. White blood and platelets, where this deficiency appears in blood tests, which results in the symptoms associated with this defect.

Leukemia cells may also invade other areas of the body which can also cause symptoms.

Symptoms of low red blood cell count (anaemia): Red blood cells carry oxygen to all cells of the body, so low red blood cells can cause symptoms such as:

feeling tired
feel helpless
feeling cold
feeling dizzy
Shortness of breath
Pale skin
Symptoms of lack of normal white blood cells: White blood cells help the body fight germs. Children with leukemia often suffer from high white blood cells, but most of them are cells caused by leukemia that do not have the ability to protect the body from infection and there are not enough normal white blood cells Which can lead to:

Infections: which can occur due to the lack of normal white blood cells. Children with leukemia can get infections that seem to not go away, or they may get one infection after another.
Fever: This is often the main sign of infection, but some children may have a fever without an infection.

Symptoms of low platelet count: Platelets help stop bleeding, so a lack of platelets can lead to:

Ease of bruising and bleeding
frequent or severe nosebleeds
bleeding gums
Bone and joint pain: This pain is caused by the accumulation of leukemia cells near the surface of the bone or inside the joint.

Abdominal enlargement: Leukemia cells can collect in the liver and spleen, making these organs larger. This may be seen as fullness or swelling in the abdomen. The lower ribs usually cover these organs but when they become enlarged they can be felt by the doctor.

Loss of appetite and weight loss: If the spleen and/or liver becomes enlarged enough it can put pressure on other organs such as the stomach and this can make the child feel full after eating a small amount of food resulting in loss of appetite and weight loss over time.

Enlarged lymph nodes: Some leukemias spread to the lymph nodes and the swollen nodes can be seen or felt as lumps under the skin or in certain parts of the body (such as the sides of the neck, in the areas under the armpits, above the collarbone, or in the groin). Lymph nodes inside the chest or abdomen can become enlarged and can only be seen on imaging tests such as a CT scan or MRI.

In children and infants, the lymph nodes often swell as they fight infection. Swollen lymph nodes in a child are more often a sign of infection than leukemia, but they should be checked by a doctor and closely followed.

Coughing or difficulty breathing: Some types of leukemia can affect structures in the middle of the chest, such as the lymph nodes or the thymus (a small organ in front of the windpipe). Enlarged thymus or lymph nodes in the chest can press on the windpipe, causing coughing or difficulty breathing. In some cases where the white blood cell count is too high, leukemia cells can build up in the small blood vessels of the lungs, which can also make it difficult to breathe.

Swelling of the face and arms: The enlarged thymus gland may press on the superior vena cava (SVC) (a large vein that carries blood from the head and arms to the heart), which can lead to "blood back" in the veins. This is known as SVC syndrome. It can lead to swelling of the face, neck, arms, and upper chest (sometimes a bluish-red skin color). Symptoms can also include headache, dizziness, and a change in consciousness if it affects the brain. SVC syndrome can be life-threatening and should be treated immediately.

Headaches, seizures and vomiting: A small number of children have leukemia that has already spread to the brain and spinal cord when it was first detected. This can lead to symptoms such as headaches, difficulty concentrating, weakness, seizures, vomiting, balance problems and blurred vision.

Rashes or gum problems: In children with acute myeloid leukemia (AML), leukemia cells may spread to the gums, causing swelling, pain and bleeding.

If acute myeloid leukemia (AML) spreads to the skin, it can cause small, dark spots that look like a common rash. Clusters of AML cells that form under the skin or in other parts of the body are called granulomas or granulocytic sarcomas.

Extreme tiredness and weakness: A rare but very serious consequence of acute myeloid leukemia (AML) is extreme tiredness, weakness, and slurred speech. This can happen when too many leukemia cells thicken the blood and slow blood circulation through the small blood vessels in the brain.

Once again we repeat that most of the symptoms listed above are likely to be caused by something other than leukemia however it is important that a doctor examines these symptoms so that the cause can be found and treated if necessary.

Pediatric Leukemia Tests

Medical history and physical examination:
If your child has signs and symptoms that suggest he may have leukemia, the doctor will want to get a comprehensive medical history to learn about symptoms and how long they've had them. The doctor may also ask about exposure to potential risk factors and it may also be important to know if there is a family history of cancer, especially leukemia.

During the physical exam, your doctor will look for any swollen lymph nodes, areas of bleeding or bruising, or possible signs of infection. The eyes, mouth, and skin will be carefully examined, a nervous system examination may be done, and the child's abdomen will be palpated for signs of an enlarged spleen or liver.

Tests to look for leukemia in children

If the doctor thinks your child may have leukemia, blood and bone marrow samples will need to be tested to confirm. Your child's doctor may refer you to a pediatric oncologist, a doctor who specializes in childhood cancers (including leukemia) for some of these tests. If leukemia is found, other types of tests may also be done to help guide treatment.

Blood tests

The first tests that are done to look for leukemia are blood tests. Blood samples are usually taken from a vein in the arm but in infants and younger children it may be taken from other veins (such as the feet or scalp) or from the 'finger'.

Blood counts and blood smears are the usual tests done on these samples. A complete blood count (CBC) is done to determine the number of blood cells of each type in the blood. For a blood smear, a small sample of blood is spread on a glass slide and examined under a microscope. Abnormal numbers of blood cells and changes in the shape of these cells may cause a doctor to suspect leukemia.

Most children with leukemia have too many white blood cells and not enough red blood cells and/or platelets. Many of the white blood cells in the blood will be blasts, an early type of blood cell usually found only in the bone marrow. Although these findings may make a doctor suspect a child has leukemia, the disease usually can't be diagnosed with certainty without looking at a sample of bone marrow cells.

Bone marrow aspiration and biopsy:

Bone marrow aspiration and bone marrow biopsy are tests that are usually done at the same time. Samples are usually taken from the back of the pelvic (hip) bones, but sometimes they may be taken from the front of the pelvic bones or from other bones.

Before the tests, the skin over the hip bone is cleaned and numbed by injecting a local anesthetic or applying an anesthetic cream. In most cases, the child is also given other medicines to make them sleepy or even sleep during the tests.

For a bone marrow biopsy, a thin, hollow needle is inserted into the bone and a syringe is used to suck out (aspiration) a small amount of liquid bone marrow.
A bone marrow biopsy is usually done right after aspiration in which a small piece of bone and marrow is removed with a slightly larger needle that is pushed down into the bone. Once the biopsy is complete, pressure will be applied to the site to help stop any bleeding.
The samples are then sent to a laboratory for testing.

Bone marrow tests are used to diagnose leukemia but can be repeated later to see if the leukemia responds to treatment.

Lumbar puncture (spinal tap):

This test is used to look for leukemia cells in the cerebrospinal fluid (CSF), the fluid that bathes the brain and spinal cord.

To perform this test, the doctor first applies a numbing cream to an area in the lower back, above the spine. The doctor will usually also give the child medicine to make him sleep during the procedure. A small, hollow needle is then placed between the bones of the spine to draw out some of the fluid, which is then sent to a laboratory for testing.

In children who have already been diagnosed with leukemia, a lumbar puncture may also be used to administer chemotherapy drugs into the cerebrospinal fluid to try to prevent or treat the spread of leukemia to the spinal cord and brain. (This is known as intrathecal chemotherapy.)

Laboratory tests to diagnose and classify leukemia

Microscopic examination:

All samples taken (blood, bone marrow, lymph node tissue, cerebrospinal fluid) are examined under a microscope.

Doctors will look at the size, shape and patterns of staining of blood cells in the samples to classify them into specific types.

The key factor is whether the cells appear mature (like normal blood cells) or immature (lack features of normal blood cells). Most of the immature cells are called blasts, of which the presence of too many in the sample, especially in the blood, is a typical sign of leukemia.

An important feature of the bone marrow sample is its cellularity as normal bone marrow contains a certain number of hematopoietic cells and fat cells. Marrow with too many hematopoietic cells is said to be hypercellular. If too few hematopoietic cells are found, the marrow is called oligodendrocyte.

Other blood tests

Children with leukemia will have tests to measure certain chemicals in the blood to check how well the body's systems are working.

These tests are not used to diagnose leukemia but are done in children known to have it, as they can help detect damage to the liver, kidneys or other organs due to the spread of leukemia cells or some chemotherapy drugs. Tests are often done to measure levels of important minerals in the blood and also to make sure the blood is clotting properly.

Children can also do these tests to detect blood infections. It is important to diagnose and treat infections quickly in children with leukemia because their weakened immune systems can allow the infection to spread.

Imaging tests

Imaging tests use X-rays, sound waves, magnetic fields, or radioactive particles to make pictures of the inside of the body. Leukemias don't usually form tumors, so imaging tests aren't as helpful as they are for other types of cancer. But if leukemia is suspected or diagnosed, your child's doctor may order some of these tests to get a better idea of the extent of the disease or to look for other problems such as infection.

Chest X-ray

A chest X-ray can help detect enlarged thymus glands or lymph nodes in the chest. If the test result is abnormal, a computerized tomography (CT) scan of the chest may be done for a more detailed view.

A chest X-ray can also help check for pneumonia if your child has a lung infection.

computerized tomography (CT) scan

A CT scan usually isn't needed for children with leukemia, but it may be done if a doctor suspects leukemia is growing in lymph nodes in the chest or in organs such as the spleen or liver. It is also sometimes used to look at the brain and spinal cord but an MRI scan may also be used for this purpose.

PET/CT scan: Some devices combine a CT scan with a positron emission tomography (PET) scan that can provide more information about any abnormal areas seen on a CT scan.

Magnetic resonance imaging (MRI)

An MRI scan, as in a CT scan, makes detailed pictures of the body's soft tissues. It's very useful for looking at the brain and spinal cord, so it's likely to be done if the doctor has reason to believe that the leukemia may have spread there ( (such as if the child has symptoms such as headaches, seizures, or vomiting) It should be noted that this test does not expose the child to radiation.

Ultrasound

Ultrasound may be used to examine lymph nodes near the surface of the body or to look for enlarged organs within the abdomen such as the kidneys, liver, and spleen. (It cannot be used to examine organs or lymph nodes in the chest because the ribs block sound waves.)

This is a fairly easy test and does not use any radiation.

Types of leukemia in children:

The type and subtype of leukemia play a major role in both treatment and prognosis options. The type (acute lymphocytic leukemia (ALL), acute myeloid leukemia (AML), etc.) and subtype of leukemia is determined by testing samples of blood, bone marrow, and sometimes lymph nodes or cerebrospinal fluid (CSF).

acute lymphoblastic leukemia (ALL)
Acute lymphoblastic leukemia (ALL) is a rapidly growing cancer of the cell-forming lymphocytes called lymphoblasts. There are several subtypes of ALL which are mainly based on:

The type of lymphocyte (often a B cell or T cell) that the leukemia cells come from (and how mature the cells are) This is known as the leukemia immunophenotype.
If the leukemia cells contain certain genetic or chromosomal changes.
B-cell ALL
Leukemia most often begins in children with ALL with early forms of B cells. There are several subtypes of ALL B cells. Mature B-cell ALL (a rare subtype) is essentially the same as Burkitt's lymphoma (a type of non-Hodgkin's lymphoma) and is treated in the same way.

T-cell ALL
This type of leukemia affects older children more than B-cell leukemia ALL. It often causes the thymus (a small organ in front of the windpipe) to enlarge, which can sometimes lead to breathing problems. It may also spread to the cerebrospinal fluid (the cerebrospinal fluid that surrounds the brain and spinal cord) early in the course of the disease.

Acute myeloid leukemia (AML)
Acute myeloid leukemia (AML)

Acute myeloid leukemia (AML) is usually a rapidly growing cancer that begins in one of the following types of early (immature) bone marrow cells:

Myeloblasts, Monoblasts, Erythroblasts, Megakaryoblasts
Survival rates for pediatric leukemia patients:

The 5-year survival rate refers to the percentage of children who live at least 5 years after their leukemia diagnosis. With acute leukemia (ALL or AML) children who have cleared the disease after 5 years are very likely to have been cured since it is very rare for these cancers to return after this long period.

acute lymphoblastic leukemia (ALL)

The 5-year survival rate for children with acute lymphoblastic leukemia has increased significantly over time and is now around 90% overall.

Acute myelogenous leukemia (AML)

The 5-year survival rate for children with AML has also increased over time and is now in the range of 65% to 70%. However, survival rates vary depending on the AML subtype and other factors.