What Do We Know About Pediatric Acute Lymphoblastic Leukemia (ALL)?

Overview of Pediatric ALL

Pediatric acute lymphoblastic leukemia (ALL), also known as acute lymphocytic leukemia, is a type of cancer that affects the blood and bone marrow. It occurs when the bone marrow produces too many immature white blood cells, known as lymphoblasts, which cannot fight infections.

ALL is the most common cancer in children, accounting for about 25% of all childhood cancers in the United States. It typically affects children between the ages of 1 and 4 years.

Subtypes of Pediatric ALL

Pediatric ALL has several subtypes, each with unique genetic characteristics. Understanding the specific subtype is crucial for determining the best treatment approach and predicting the patient’s prognosis. The two main categories of ALL are B-cell and T-cell variants.

• B-Cell ALL: The most common type in children. It begins with immature B-lymphocytes.

• High Hyperdiploid B-ALL: Characterized by an abnormal number of chromosomes.

• ETV6::RUNX1 Fusion Positive B-ALL: A translocation that typically carries a good prognosis.

• BCR-ABL1 Positive B-ALL (Philadelphia Chromosome Positive): This subtype generally has a poorer prognosis but can be targeted with tyrosine kinase inhibitors.

• T-Cell ALL: Less common in children but more frequent in adults.

Prognostic Factors in Pediatric ALL

Children with ALL are categorized into different risk groups — standard risk, high risk, and very high risk — to help guide treatment decisions and predict outcomes. Risk stratification considers several prognostic factors, such as:

• Age: ALL tends to be more aggressive in children younger than 1 year or older than 10 years.
• White Blood Cell Count: A higher white blood cell count at diagnosis (above 50,000 per microliter) often indicates a need for more aggressive treatment.
• Biomarkers: Specific genetic changes in the leukemia cells, such as chromosomal or gene alterations, can affect how easily the cancer responds to treatment.

Symptoms of Pediatric ALL

ALL symptoms occur when the bone marrow is overwhelmed by immature blood cells that cannot function properly. Common symptoms in children with ALL include:

• Bleeding, bruising, and frequent nosebleeds.
• Petechiae: Small red or purple spots on the skin caused by bleeding.
• Fever, fatigue, and joint pain.
• Loss of appetite or shortness of breath.
• Swollen lymph nodes.
• Unexplained weight loss.

The Hopeful Prognosis of Pediatric ALL

With prompt diagnosis and treatment, most children with ALL are cured. The disease can develop quickly, making early detection and treatment crucial. Pediatric ALL has a positive prognosis overall, with a 5-year survival rate of 90%.

Effective treatment protocols, including chemotherapy, radiation therapy, and sometimes targeted therapies, have significantly improved survival rates. ALL is one of the most treatable cancers in children.

Sources:

• National Cancer Institute (NCI): Childhood Acute Lymphoblastic Leukemia (ALL) Overview
• American Cancer Society: Childhood Acute Lymphoblastic Leukemia
• St. Jude Children's Research Hospital: Acute Lymphoblastic Leukemia (ALL) Treatment
• American Society of Hematology: Acute Lymphoblastic Leukemia