Childhood Acute Lymphocytic Leukemia (ALL): Comprehensive Cancer Information

Childhood Acute Lymphocytic Leukemia (ALL): A Comprehensive Guide

General Information

Leukaemia is an umbrella term used for cancers that affect the blood and the body's blood-forming tissues. Among children, Acute Lymphocytic Leukaemia (ALL) is the most frequently diagnosed type.

Understanding Blood Cell Production

Millions of blood cells are produced by the body every day, primarily developing in the bone marrow—the spongy material inside bones that contains immature stem cells.

In a healthy individual, these immature stem cells first mature into either lymphoid stem cells or myeloid stem cells.

Lymphoid stem cells

Lymphoid stem cells develop into white blood cells, which are crucial components of the immune system. They start as immature white blood cells called lymphoblasts and then mature into lymphocytes. The two types of lymphocytes commonly involved in leukaemia are B cells and T cells. B cells produce antibodies to attack invading bacteria and viruses, while T cells help alert other immune cells or fight infection directly.

Myeloid stem cells

Myeloid stem cells also develop into white blood cells. They begin as immature white blood cells known as myeloblasts, which then mature into monocytes and granulocytes, including neutrophils—all of which combat disease. Other myeloid stem cells develop into red blood cells (which transport oxygen) and platelets (which help the blood clot).

Leukaemia occurs when the DNA (the genetic instructions controlling cell activity) of a bone marrow stem cell changes or mutates during its development. This cell becomes cancerous, starts multiplying rapidly, and crowds out 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

The four most common types of leukaemia are classified based on:

1. Cell Type

The type of stem cell that has become cancerous—either lymphoid or myeloid.

2. Progression

Whether the disease is acute or chronic.

  • Acute leukaemia affects immature cells, stopping them from developing and functioning correctly. These cells multiply quickly, making acute leukaemia more aggressive. Nearly all childhood leukaemias are acute.
  • Chronic leukaemia involves mature or partially mature cells. These cells multiply more slowly, making it less aggressive than acute leukaemia. Chronic leukaemia is rare in children.

About Childhood ALL

ALL develops from lymphoid stem cells. These cancerous cells multiply rapidly and are poor at fighting infection. They also crowd out healthy cells, which leaves patients with ALL feeling weak and susceptible to infection.

There are two primary subtypes of ALL: B cell, which accounts for about 85% of cases, and T cell, which accounts for 15%. Further subtypes are determined by various chromosome abnormalities in the cancer cells and the types of molecules these cells produce. These specific classifications can influence a patient's treatment plan and outlook.

many cases are diagnosed in India each year, with more than half occurring in paediatric patients. The number of paediatric cases is highest between the ages of 2 and 3, with a smaller rise during the teenage years.

Fortunately, ALL is highly treatable. The five-year survival rate for paediatric patients is approximately 90% for children under 14 and 75% for those aged 15–19. The specific ALL subtype and cancer characteristics can affect a patient's long-term outlook.

Childhood ALL Risk Factors

A risk factor is anything that increases the likelihood of developing a disease. Knowing these factors can be an important step towards early detection, though it is important to remember that not everyone with risk factors will develop the disease.

Risk factors for childhood ALL include:

  • Exposure to X-rays before birth.
  • Previous treatment with chemotherapy or radiation therapy for an earlier cancer. While these treatments carry a small risk of causing other leukaemias, their benefits in cancer treatment far outweigh this risk.

Genetic disorders

Individuals with certain genetic conditions have a higher risk of developing some leukaemias. These include:

  • Li Fraumeni syndrome, a hereditary cancer syndrome
  • Ataxia telangiectasia
  • Bloom syndrome
  • Down syndrome
  • Fanconi anaemia

Genetic Counselling

Some cases of leukaemia can be passed down through generations. Genetic counselling may be appropriate for you to learn more about the risk to you and your family.

Symptoms

Although there are various 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 throughout the body, fight infection, and stop bleeding. Some symptoms may also be due to low levels of haemoglobin, the protein that helps transport oxygen.

Leukaemia symptoms may include:

  • Weakness, tiredness, and fatigue. This can be caused by the leukaemia itself or by the low haemoglobin levels commonly seen in many leukaemia patients.
  • 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 nosebleeds.
  • Petechiae, a rash-like cluster of pinpoint spots on the skin caused by bleeding into the skin, also resulting from low platelet levels.
  • Shortness of breath, which can be caused by low haemoglobin levels and lung infections.
  • Swollen lymph nodes in the neck, underarm, stomach, or groin.
  • Loss of appetite or feeling full after eating very little food due to an enlarged spleen.
  • Unexplained weight loss.
  • Bone and joint pain.
  • For female patients, menstruation that is longer or heavier than usual.

Diagnosis

A leukaemia diagnosis typically begins with a simple blood test, known as a complete blood count, which a doctor may order after evaluating the patient's symptoms or as part of a routine check-up.

If the test results indicate the presence of leukaemia cells or abnormal levels of red blood cells, white blood cells, or platelets, doctors may order additional tests. These tests can provide a definitive leukaemia diagnosis and determine the extent of the disease. They are also used to monitor the disease's progression and track its response to treatment.

At SSCHRC, 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.

Key Diagnostic Procedures

Biopsy

For leukaemia, patients undergo a bone marrow biopsy. This procedure involves taking a sample of bone marrow from the hip using a needle to determine if cancerous cells are present.

Genetic and Molecular Testing

If leukaemia is diagnosed, further tests can determine if specific chromosomes or gene mutations are present in the diseased cells, or if they have particular proteins or molecules on their surface. This process, sometimes called molecular profiling, helps doctors identify the patient's exact type of leukaemia and their prognosis. Cancers with different genetic and molecular characteristics may respond differently to treatments, so these tests help doctors create the most effective treatment plan.

Lumbar Puncture (Spinal Tap)

Although leukaemia starts in the bone marrow, it can spread to the central nervous system (the brain and spinal cord), which is most common in acute lymphocytic leukaemia. A lumbar puncture involves using a needle to remove cerebrospinal fluid from the spine for examination. A small dose of chemotherapy may also be administered into the spinal fluid during this procedure 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 ALL Risk Groups

There is no standard staging system for childhood ALL; instead, the disease is divided into risk groups:

Standard (low) risk

Includes children aged 1 to younger than 10 years who have a white blood cell count of less than 50,000/microliter at the time of diagnosis.

High risk

Includes children 10 years and older and/or children who have a white blood cell count of 50,000/microliter or more at the time of diagnosis.

Very high risk

Includes children younger than age 1, children with certain genetic changes, children who show a slow response to initial treatment, and children who have signs of leukaemia after the first four weeks of treatment.

Treatment

At SSCHRC, your child's health and well-being are the top priority. Our experts customise care for leukaemia, using the most advanced treatments and techniques to minimise the impact on your child's developing body. As part of a world-renowned cancer centre, the SSCHRC has extensive experience and skill in treating these types of cancer, which can significantly influence your child's outcome.

Customised Care Plans

A team of specially trained physicians supports your child throughout treatment and into survivorship. They communicate closely with each other and with you to ensure comprehensive, personalised care. They are supported by a full complement of dedicated healthcare professionals, including nurses, physician assistants, and therapists.

The SSCHRC offers clinical trials for innovative new leukaemia treatments and conducts groundbreaking basic science research to change the future of paediatric cancer.

Treating the Whole Child

SSCHRC is designed specifically for children, with a range of services and amenities to make the experience as comfortable as possible for the child and their family. We go beyond medical care to deliver a comprehensive experience that treats the whole child, including camp programmes, arts in medicine, and music therapy.

Acute Lymphocytic Leukaemia (ALL) Treatment Plans

Newly diagnosed childhood ALL patients typically undergo chemotherapy, which is administered in phases. Depending on the specific features of the patient's cancer, targeted therapy may also be prescribed. If the cancer returns or does not respond to initial treatment, patients may need a stem cell transplant. Young adult patients under age 25 may qualify for CAR T cell therapy if other therapies have been unsuccessful.

Treatment Modalities

Chemotherapy

Chemotherapy drugs are used to kill cancer cells, control their growth, or 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 ALL is usually given in multiple stages:

  • Induction: This is the intense first phase of treatment, designed to eliminate leukaemia cells in the blood and bone marrow. It usually requires a hospital stay. The goal is to bring the cancer into remission.
  • Post-Induction Phases: Following induction are three to four phases (consolidation, interim maintenance, delayed intensification, and interim maintenance II) designed to kill any cancer cells that survived the initial phase.
  • Maintenance: This phase follows the others, where patients receive a lower dose of chemotherapy to prevent the cancer from returning. ALL patients typically receive maintenance chemotherapy for approximately one and a half years.
  • A small dose of chemotherapy may also be given into the central nervous system via a lumbar puncture to prevent the disease from spreading to this area. Patients undergoing a stem cell transplant may also receive chemotherapy to prepare their body for the procedure.

Targeted Therapy

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

Stem Cell Transplantation (Bone Marrow Transplant)

This procedure replaces cancerous bone marrow with new, healthy bone marrow stem cells. It is usually performed after an intense round of chemotherapy that kills the patient's existing bone marrow cells. Patients typically need to stay in the hospital for three to four weeks after the procedure.

A stem cell transplant may be necessary if the leukaemia has returned, has not responded to standard treatments, or if the patient has a high-risk form of leukaemia that makes a cure with standard treatments unlikely. This treatment can be physically challenging and is usually not given to older or otherwise unhealthy patients.

Radiation Therapy

This uses powerful beams of energy to kill cancer cells. Since leukaemia cells travel in the bloodstream, there is no distinct tumour to target. Instead, radiation may be used when the disease has spread to the central nervous system.

CAR T Cell Therapy

T cells are a type of immune system cell that helps the body respond to disease and directly kills diseased cells. In CAR T cell therapy, T cells are modified in a lab so they can recognise and attack cancer cells.

Monoclonal Antibody Therapy

This is a type of immunotherapy. Monoclonal antibodies attach to specific proteins on the surface of cancer cells or immune cells. They either mark the cancer as a target for the immune system or boost the ability of immune cells to fight the cancer.

Clinical Trials

As a top-ranked cancer centre, SSCHRC offers multiple clinical trials for ALL, many of which are unavailable elsewhere. These trials explore new drug combinations and new drugs, including targeted therapies and immunotherapies.

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