Most Common Cancer in Children
Acute lymphoblastic leukemia (ALL) is definitively the most common cancer in children, representing 75-80% of acute leukemias and accounting for approximately 25% of all pediatric cancer diagnoses. 1
Epidemiologic Data
- ALL is the most common pediatric malignancy, with an age-adjusted incidence rate of 1.38 per 100,000 individuals per year in the United States 1
- Approximately 55.4% of ALL patients are diagnosed before age 20 years, with a median age at diagnosis of 15 years 1
- Leukemia overall accounts for approximately 28-31% of all childhood cancers, making it the leading cancer type in this population 1
- Among leukemias in children, ALL comprises more than 80% of cases, with acute myeloid leukemia (AML) representing only approximately 20% 1
Clinical Context and Prognosis
- The 5-year overall survival rate for pediatric ALL has improved dramatically to 89% in children, though outcomes are significantly worse in adolescents and young adults (61%) and infants under 1 year (58.2%) 1
- Despite high cure rates, ALL remains a leading cause of cancer-related death in children, particularly in relapsed or refractory cases 2, 3
- Current survival rates of 80-90% represent a remarkable improvement from approximately 10% in the 1960s, achieved through risk-adapted multiagent chemotherapy, improved supportive care, and molecular characterization 2, 3
Other Common Pediatric Cancers for Comparison
- Central nervous system (CNS) tumors are the second most common pediatric malignancy and the leading cause of cancer-related death in children 4
- Neuroblastoma is the most common extracranial solid tumor in children 4
- Lymphomas (both Hodgkin and non-Hodgkin) represent another significant category but are less common than ALL 1
Important Clinical Pitfall
Do not delay obtaining a complete blood count with manual differential in any child with concerning symptoms (unexplained fever, bruising, bone pain, lymphadenopathy, or hepatosplenomegaly), as ALL can present with subtle findings that may be initially attributed to viral illness. 5 Manual review by an experienced technician is mandatory, as automated counters may miss circulating blasts or dysplastic features that indicate leukemia 5