Prevalence of Medulloblastoma in Children Under 15
The estimated prevalence of medulloblastoma in pediatric patients (under 15 years) in the United States is approximately 1,423 cases, with an incidence rate of 0.47 per 100,000 children aged 0-14 years. 1
Epidemiologic Data
Overall Burden
- Medulloblastoma accounts for 10-20% of all pediatric brain tumors, making it one of the most common malignant brain tumors in children 1
- The tumor represents approximately 60% of childhood intracranial embryonal tumors 2
- In the United States, the total estimated prevalence across all age groups is 3,835 cases, with pediatric cases (under 15 years) comprising 1,423 of these 1
Age Distribution Patterns
- The average age at diagnosis is 6.5 years, with the highest frequency occurring at age 3 years 3
- Case frequency decreases progressively in each successive 5-year age interval from birth to 20 years 3
- Patients under 3 years represent a distinct high-risk subgroup with worse outcomes 1
Sex Distribution
- The male-to-female ratio is approximately 1.33:1, indicating a modest male predominance 3
- Sex distribution varies by molecular subtype, with certain subgroups showing different gender predilections 1
Molecular Subtype Distribution in Pediatric Patients
The prevalence varies significantly by molecular subgroup, which has critical prognostic implications:
- WNT-activated tumors: 10% of cases, most common in children aged 7-14 years with excellent prognosis (>90% long-term survival) 1
- SHH-activated tumors: 10-20% of cases, with prognosis dependent on TP53 mutation status 1
- Group 3 tumors: 25-35% of cases, associated with poor prognosis (20-30% 5-year survival) 1
- Group 4 tumors: 25-35% of cases, with better outcomes (75-90% survival rates) 1
Clinical Context and Survival
- With modern multimodal therapy, approximately 75% of children with medulloblastoma achieve prolonged survival 1, 4
- The risk of mortality has been reduced by 30% over the past 20 years due to advances in treatment 4
- High-risk patients (those under 3 years, with metastatic disease, or suboptimal resection) experience 5-year overall survival of less than 70% 2
Important Caveats
Referral to specialized centers is critical given the rarity of this tumor—even academic brain tumor centers see only a small number of pediatric medulloblastoma cases annually, making expertise concentration essential for optimal outcomes 1