Background
Phase III RCT (Baby POG I). 198 infants and young children (<3 years) with brain tumors (medulloblastoma, PNET, ependymoma, astrocytoma). Randomized to postoperative chemotherapy to delay RT vs immediate RT. Primary aim: test whether intensive upfront chemotherapy could defer or avoid cranial/craniospinal RT in young children, preserving neurodevelopment.
Interventions and follow up
Arm A: Immediate craniospinal RT (35–36 Gy CSI + boost) after surgery
Arm B: Postoperative chemotherapy (cyclophosphamide + vincristine + cisplatin + etoposide, 12 weeks) to delay RT — RT given only at progression or completio
Primary endpoint: 2-year PFS
mFollow up: 5.0 year
Arm B: Postoperative chemotherapy (cyclophosphamide + vincristine + cisplatin + etoposide, 12 weeks) to delay RT — RT given only at progression or completio
Primary endpoint: 2-year PFS
mFollow up: 5.0 year
Results
2-yr PFS (chemo delay, medulloblastoma): 40% vs RT immediate 78%
5-yr OS (medulloblastoma): Chemotherapy arm inferior; ~30% 5-yr OS in chemo group
Ependymoma 5-yr EFS: Chemotherapy arm: 23% vs RT: 33% (non-significant trend)
5-yr OS (medulloblastoma): Chemotherapy arm inferior; ~30% 5-yr OS in chemo group
Ependymoma 5-yr EFS: Chemotherapy arm: 23% vs RT: 33% (non-significant trend)
Adverse events
Main adverse events: RT arm: significant neurocognitive damage — IQ <70 in 50% at 3 years; growth failure; endocrinopathy. Chemotherapy arm: myelosuppression, nephrotoxicity, ototoxicity; treatment-related deaths in 6%.
Conclusions
Delaying RT with chemotherapy in infants with medulloblastoma resulted in inferior tumor control compared to immediate RT, though chemotherapy allowed RT deferral in a subset. The severe neurocognitive toxicity of CSI in infants makes RT avoidance a worthy goal despite inferior disease control.
Key Limitations
Key Limitations: Heterogeneous patient population with different tumor types analyzed together. Chemotherapy regimen was not optimized for current standards. Does not inform modern infant protocols using high-dose chemotherapy with stem cell rescue or intraventricular topotecan.
Clinical Context
Baby POG I established the rationale for chemotherapy-first approaches in infants with brain tumors despite inferior disease control. It confirmed the severe neurotoxicity of early CSI. Modern infant protocols (Head Start, SJYC07) use intensive chemotherapy to avoid or defer RT, with improved outcomes. CSI is generally avoided under age 3 at most centers.
References
References: Geyer JR et al, JCO 2005; PMID: 11554387