Childhood Acute Myeloid Leukaemia (AML): Comprehensive Cancer Information

Childhood Acute Myeloid Leukaemia (AML): A Comprehensive Guide

This information is intended to provide a general overview of Childhood Acute Myeloid Leukaemia (AML). It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with a qualified healthcare provider for any health concerns or before making any decisions related to your health.

General Information

Leukaemia is the umbrella term for cancers that affect the blood and the blood-forming tissues within the body. While it is considered a rare disease, paediatric Acute Myeloid Leukaemia (AML) is the second most commonly diagnosed type of leukaemia in children.

Understanding Blood Cell Production

The body is constantly producing millions of new blood cells every day, with the process primarily occurring in the bone marrow, the spongy tissue found inside bones that houses immature stem cells. In a healthy individual, these immature stem cells develop into two main types:

Lymphoid Stem Cells

These mature into white blood cells, which are crucial for the immune system. They first become immature cells called lymphoblasts and then mature into various types of lymphocytes, such as B cells (which produce antibodies to fight bacteria and viruses) and T cells (which alert other immune cells and fight infections directly).

Myeloid Stem Cells

These also develop into certain white blood cells (like monocytes and granulocytes, including neutrophils, which fight disease), as well as red blood cells (which carry oxygen) and platelets (which help blood to clot).

Leukaemia occurs when the genetic instructions (DNA) within a bone marrow stem cell mutate at some point during its development. This cell becomes cancerous, begins to multiply uncontrollably, and quickly overwhelms the healthy cells in the blood and bone marrow. These diseased cells can also build up in other areas of the body, such as the liver, lymph nodes, spleen, and skin.

Classification of Leukaemia

Leukaemias are broadly classified based on the type of stem cell that becomes cancerous (either lymphoid or myeloid) and the speed of the disease's progression:

Acute Leukaemia

This involves immature cells, preventing them from developing correctly and performing their function. These cells multiply rapidly, making acute leukaemia more aggressive. Almost all childhood leukaemias are acute.

Chronic Leukaemia

This involves mature or partially mature cells that multiply more slowly, making it less aggressive than the acute form. Chronic leukaemia is rare in children.

About Childhood AML

AML develops from myeloid stem cells. It occurs after a myeloid stem cell develops into a myeloblast, which should mature into a healthy white blood cell. However, in AML, the cell mutates into a leukaemic cell and cannot develop normally. These diseased cells are unable to function properly and multiply rapidly, crowding out healthy blood cells as the disease progresses.

As a result, AML, like other leukaemias, can lead to:

  • Anaemia (due to a lack of red blood cells).
  • Poor blood clotting (due to a lack of platelets).
  • A severely weakened immune system, leading to frequent and severe infections (due to a lack of healthy white blood cells).

AML has several subtypes, many of which depend on specific chromosome abnormalities and the types of molecules produced by the cancer cells. These specific subtypes are important factors that guide the patient's treatment plan and outlook.

Childhood AML Risk Factors

A risk factor is anything that increases the chance of developing a disease. It is important to note that the presence of risk factors does not mean a child will definitely develop AML. Risk factors for childhood AML include:

  • Family History: Having a sibling with leukaemia, especially an identical twin, is a known risk factor.
  • Myelodysplastic Syndrome (MDS): This condition, where the bone marrow does not produce enough healthy blood cells, can progress into AML.
  • Genetic Disorders: Certain inherited disorders increase the risk of developing AML. These include Down syndrome and hereditary cancer syndromes such as Li-Fraumini Syndrome.
  • Previous Cancer Treatment: Past treatment with chemotherapy or radiation therapy for a previous cancer. While these therapies are AML risk factors, their benefits as cancer treatments far outweigh the risks they carry.
  • Chemical Exposure: Long-term exposure to benzene, a chemical used in the petroleum industry, can cause AML.

Symptoms

While there are many different types of leukaemia, the symptoms they cause can be similar. Many symptoms arise from a lack of properly functioning blood cells, which are necessary to carry oxygen, fight infection, and stop bleeding. Some symptoms may also be due to low levels of haemoglobin, the protein that moves oxygen through the body.

Common leukaemia symptoms include:

  • Weakness, tiredness, and fatigue: Often caused by the leukaemia itself or low haemoglobin levels (anaemia).
  • Fever and frequent infections: Due to low counts of healthy white blood cells.
  • Excessive sweating or night sweats.
  • Easy bleeding and bruising: Including bleeding of the gums, due to low platelet levels.
  • Recurrent nose bleeds.
  • Petechiae: A rash-like collection of pinpoint spots on the skin caused by bleeding into the skin, also due to low platelet levels.
  • Shortness of breath: Can be caused by low haemoglobin levels and lung infections.
  • Swollen lymph nodes: In the neck, underarm, stomach, or groin.
  • Loss of appetite or a full feeling after eating very little food: Due to enlargement of the spleen.
  • Unexplained weight loss.
  • Bone and joint pain.
  • For female patients: Menstruation that is longer or heavier than normal.

Diagnosis

Successful leukaemia treatment starts with an accurate and precise diagnosis. At SSCHRC, our suspected leukaemia cells are examined by pathologists who specialise exclusively in diagnosing leukaemia and its many subtypes. This focused expertise allows SSCHRC to offer patients the most effective treatment for their specific disease.

Diagnosing Leukaemia

Complete Blood Count (CBC)

A leukaemia diagnosis usually begins with a simple blood test called a CBC. A doctor may order this test after evaluating a patient's symptoms, or it may be part of a routine check-up. If the test shows the presence of leukaemia cells or abnormal levels of red blood cells, white blood cells, or platelets, further tests may be ordered.

Biopsy

For leukaemia, patients undergo a bone marrow biopsy. This involves taking a sample of bone marrow from the hip with a needle to determine if cancerous cells are present. The retrieved suspected cancer cells are then studied under a microscope.

Genetic and Molecular Testing (Molecular Profiling)

If leukaemia is diagnosed, additional tests can determine if specific chromosomes or gene mutations are present in the diseased cells, or if they have specific proteins or molecules on their surface. This process helps doctors determine the patient's exact type of leukaemia and their prognosis, which is vital for creating a treatment plan with the best chance of success, as cancers with different genetic features may respond differently to treatments.

Lumbar Puncture (Spinal Tap)

While leukaemia starts in the bone marrow, it can potentially spread to the central nervous system (the brain and spinal cord). A lumbar puncture is used to check for this spread by examining the patient's spinal fluid. During the procedure, a needle is used to remove cerebrospinal fluid from the spine. A small dose of chemotherapy may also be administered into the spinal fluid to kill any leukaemia cells that may be present.

Imaging Exams

Doctors may order imaging exams to check for the presence of cancer in different parts of the body.

Childhood AML Descriptions

Since there is no standard staging system for AML, the disease is described by the patient's treatment and disease status:

Newly Diagnosed Childhood AML

Cancer that has not been treated (except to relieve symptoms like fever, bleeding, or pain) and has one of the following:

  • More than 20% of the cells in the bone marrow are blasts (leukaemia cells).
  • Less than 20% of the cells in the bone marrow are blasts, but a certain chromosome change is present.

Childhood AML in Remission

The disease has been treated, and the following are found:

  • The complete blood count is almost normal.
  • Less than 5% of the cells in the bone marrow are blasts.
  • There are no signs or symptoms of leukaemia in the brain, spinal cord, or other parts of the body.

Refractory Leukaemia

Cancer that does not respond to treatment.

Recurrent Leukaemia

Cancer that has returned (come back) after it has been treated. The cancer may return in the blood, bone marrow, or in other parts of the body, such as the central nervous system.

Treatment

At SSCHRC, we understand that your child's health and well-being are your highest priority. Our renowned experts tailor your child's leukaemia care using the most advanced treatments and techniques with the least impact on your child's growing body. As part of one of the world's most active cancer centres, SSCHRC has exceptional experience and skill in treating these cancers, which can make a significant difference to your child's outcome.

Customised Leukaemia Care Plans

A team of specially trained physicians manages your child's care throughout treatment, all the way to survivorship. They communicate closely with each other and with you to ensure comprehensive, personalised care. They are supported by a full complement of healthcare professionals dedicated to your child's treatment, including nurses, physician assistants, and therapists. SSCHRC offers clinical trials for innovative new treatments for leukaemia and is involved in groundbreaking basic science research to change the future of paediatric cancer.

AML Treatment Plans

Treatment for newly diagnosed childhood AML patients typically focuses on chemotherapy. Stem cell transplantation is also an important treatment option for AML. It may be an initial treatment for patients with particularly aggressive and hard-to-treat types of the disease. It is also given to patients with refractory AML (meaning the disease has not responded to standard treatments) or recurrent AML (meaning the disease has returned after remission). These patients can only undergo a stem cell transplant after achieving remission with non-standard or experimental therapies.

1. Chemotherapy

Chemotherapy drugs kill cancer cells, control their growth, or help relieve disease-related symptoms. Treatment may involve a single drug or a combination of two or more drugs, depending on the type of cancer and its growth rate.

Chemotherapy for AML is usually given in two stages:

  • Induction: This is an intense treatment phase designed to kill leukaemia cells in the blood and bone marrow. It usually requires a hospital stay, and the primary goal is to bring the cancer into remission.
  • Consolidation: This phase is intended to kill any remaining cancer cells that survived the induction phase.

Patients will also receive a small dose of chemotherapy into their central nervous system to prevent the disease from spreading to this area. Patients preparing for a stem cell transplant may also undergo chemotherapy to prepare their body for the procedure.

2. Targeted Therapy

Targeted therapy drugs are designed to stop or slow the growth or spread of cancer at a cellular level. Cancer cells need specific molecules (often proteins) to survive and multiply. Targeted therapies are designed to interfere with, or 'target', these molecules or the cancer-causing genes that create them.

3. Stem Cell Transplantation

A stem cell transplant (also known as a bone marrow transplant) is a procedure that replaces cancerous bone marrow with new, healthy bone marrow stem cells. Transplants are typically given after an intense round of chemotherapy that destroys the patient's existing bone marrow cells. Patients usually need to stay in the hospital for three to four weeks after the procedure.

A stem cell transplant may be necessary for patients whose leukaemia has returned or has not responded to standard treatments. It may also be recommended if the patient has a high-risk form of leukaemia where a cure with standard treatments is unlikely. This is a physically challenging treatment, so it is typically not administered to patients who are older or otherwise unhealthy.

4. Radiation Therapy

Radiation therapy uses powerful beams of energy to kill cancer cells. Since leukaemia cells travel in the bloodstream, there is no distinct tumour to target like there is with other cancers. Instead, radiation is typically used when the disease has spread to the central nervous system.

5. Clinical Trials

As a top-ranked cancer centre, SSCHRC offers multiple clinical trials for AML. Many of these trials are unique and cannot be accessed elsewhere. Trials explore new drug combinations and new drugs, including targeted therapies and immunotherapies.

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