Acute Lymphoblastic Leukemia (ALL) is the most notorious form of cancer of blood and bone marrow in children. It is on the top for 1 to 4-year-old children but can also develop in older children and even adults. Based on the Indian cancer registries, ALL has an alarming prevalence of nearly 25 percent and constitutes one of the major childhood cancers in the country, posing a significant public health threat.
The hallmark of ALL is excessive production of immature white blood cells known as lymphoblasts which are unable to progress into B or T cells. The progeny of these leukemia cells do not mature into healthy blood cells, resulting in anemia, increased susceptibility to infections, and excessive bruising and bleeds. The disease left untreated is known to be a rapidly progressive one, but owing to advances in medicine, leukemia survival rates have improved significantly.
Understanding Blood Cells and ALL Development:
Stem cells from the blood develop progressively over time to become proliferated blood cells. These stem cells have the potential to differentiate into the following types of cells:
Myeloid Stem Cells – These give rise to:
Red Blood Cells (RBCs): These cells transport oxygen throughout the human body.
Granulocytes (White Blood Cells – WBCs): Help fight body infections.
Platelets: These assist blood in clotting and aid in healing wounds.
Lymphoid Stem Cells – Lymphoid Stem Cells differentiate into Lymphoblast Cells which further develop into:
B Lymphocytes (B cells): These cells help produce antibodies for body infection.
T Lymphocytes (T cells): These aid B cells in producing antibodies, which target infected body cells.
Natural Killer (NK) Cells: These exterminate cancerous cells and viruses in the body.
In Acute Lymphoblastic Leukemia, the lymphoblasts proliferate excessively leading to disruption in normal blood cell formation, resulting in dire health consequences.
Causes and Risk Factors of ALL:
Unmanaged growth of lymphoblasts due to genetic mutations is what triggers ALL. Unfortunately, It is often difficult to pinpoint the cause. Still, several risk factors have been determined to increase the likelihood of developing THIS disease:
Genetic Risk Factors for ALL: Some inherited genetic disorders increase the risk of ALL, including:
Down Syndrome
Neurofibromatosis Type 1
Bloom Syndrome
Fanconi Anemia
Ataxia-Telangiectasia
Li-Fraumeni Syndrome (TP53 Gene Mutation)
Constitutional Mismatch Repair Deficiency (CMMRD)
Environmental and Lifestyle Risk Factors:
Exposure to X-rays before birth
High-dose radiation exposure
Previous chemotherapy treatment
Even when certain risk factors are present, it does not mean the individual will definitely contract ALL. On the other hand, it is also possible for individuals without any risk factors to develop all.
Symptoms of Childhood ALL:
Leukemia is believed to meddle with RBCs, WBCs, and platelets which means that it can have the following symptoms:
frequent fevers
infections
easy bruising
bleeding (nosebleeds, gum bleeding)
tiny red spots (petechiae) under the skin
Fatigue
weakness
pale skin (due to anemia)
bone or joint pain
swollen lymph nodes (neck, underarms, stomach, groin)
shortness of breath
abdominal swelling or pain
loss of appetite
weight loss
This and many other symptoms are very common and therefore another illness can be the culprit, which is why professional medical advice should be sought for confirmation.
Tests to Diagnose Childhood ALL:
In children, doctors tend to use multiple methods to examine the individual to find the type and Intensity of the leukemia that they have.
Common Diagnostic Tests:
Complete Blood Count (CBC): It counts the total number of RBCs/WBCs/Platelets and measures the amount of Hemoglobin present in the blood.
Blood Chemistry Tests: This helps examine the blood for unknown or abnormal substances.
Bone Marrow Aspiration & Biopsy: It is the removal of selected material from the bone marrow for examination of the potential presence of leukemia.
Genetic Testing: It looks for specific chromosome mutations such as Philadelphia chromosomes or the TP53 mutation.
Immunophenotyping: It finds the phenotype of ALL- which is B cell or T cell type.
Lumbar Puncture (Spinal Tap): It verifies if cancerous lesions are located in the cranial cavity or spinal cord.
Chest X-ray: It identifies lesions or pathogenic neoplasm formation in the thorax.
These analyses enable physicians to create therapeutic approaches for individual patients.
Risk Groups for ALL and Treatment Approach:
To create the treatment protocol, doctors classify ALL into different risk groups:
Standard Risk:
Age: 1-10 years
White Blood Cell (WBC) count: 50,000 or less
High Risk:
Age: Over 10 years
WBC Count: 50,000 or more
Very High Risk:
Infants under 1 year of age
Some genetic alterations such as MLL rearrangement
Leukemia in cerebrospinal fluid (CSF)
Patients who fall into the high-risk category may need more intensive chemotherapy and other therapies.
Treatment Options for Childhood ALL:
Acute Lymphoblastic Leukemia (ALL) is most commonly treated through chemotherapy which can be given as an injection (IV), tablets, or into the spinal cord. The treatments that are most often used include Asparaginase, Methotrexate, Vincristine, Cytarabine, and Dexamethasone. Radiation therapy employs high-energy X-rays to kill leukemia cells while also attempting to limit excess tissue damage in case there is already an existing tumor in the brain or spine. Some stem cell transplants require high doses of chemotherapy to kill ALL leukemia cells, then healthy stem cells are infused afterward to recover blood production, which is typically performed in highly resistant or relapsed ALL. Immunotherapy, specifically CAR T-cell therapy for T-cell leukemia, is used primarily for Relapse or chemotherapy-resistant ALL. Dasatinib, Imatinib, Inotuzumab ozogamicin, and Bortezomib are some examples of targeted therapy that seeks to minimize damage to healthy cells while interfering with cancer-causing proteins.
Phases of ALL Treatment:
Induction Phase (First Month):
Goal: Kill 99% of leukemia cells.
Success Rate: 95% of children achieve remission.
Consolidation Phase (Several Months):
Goal: Eliminate remaining leukemia cells.
Treatment: More chemotherapy to prevent relapse.
Maintenance Phase (2-3 Years):
Goal: Prevent leukemia from returning.
Treatment: Lower-dose chemotherapy over time.
Following the full treatment plan reduces relapse risk.
Prognosis and Long-Term Outlook:
With early diagnosis and treatment, the 5-year survival rate for childhood ALL has increased to 85-90%. Factors influencing prognosis include:
Age & Risk Group
B-cell or T-cell leukemia type
Genetic mutations
How quickly leukemia responds to treatment
Regular follow-ups and supportive care ensure a long-term remission.
Final Thoughts:
Childhood Acute Lymphoblastic Leukemia (ALL) is curable with timely diagnosis and proper treatment. Advances in chemotherapy, targeted therapy, and immunotherapy have significantly improved survival rates. Early detection and adherence to treatment save lives. If you notice symptoms, consult a pediatric oncologist immediately.
