St. Jude Ependymoma Series

Background

Prospective institutional series. 153 children (1–22 years) with intracranial ependymoma treated at St. Jude Children's Research Hospital 1997–2007. All received risk-adapted conformal RT; chemotherapy given only for infants or recurrence. First major series to demonstrate feasibility and outcomes of conformal RT with tight margins in ependymoma.

Interventions and follow up

Arm A: Conformal RT 59.4 Gy (1.8 Gy/fx) with individualized CTV margins (0.5–1.0 cm). Craniospinal RT not used for M0 disease.
Primary endpoint: Local control, EFS, OS
mFollow up: 6.0 year

Results

7-yr local control: 67% (all patients); 74% after GTR vs 36% after STR
7-yr EFS: 63% (GTR) vs 28% (STR)
7-yr OS: 81% (GTR) vs 59% (STR)
Spinal relapse rate (M0 disease): <5% — confirmed craniospinal RT not needed for M0

Adverse events

Main adverse events: Neurocognitive decline on serial testing (IQ loss ~1–2 points/year). Endocrine dysfunction in 18%. Growth hormone deficiency 15%. No CSI-related toxicity as CSI was not used for M0 disease.

Conclusions

GTR followed by conformal RT achieves excellent local control and survival in pediatric ependymoma. Omission of CSI for M0 disease was validated — spinal failure rate was low. Extent of surgical resection is the dominant modifiable prognostic factor.

Key Limitations

Key Limitations: Single-institution series, not randomized. Selection bias in surgical resection quality. Molecular subtyping not performed (pre-WHO 2016 classification). Long-term neurocognitive and endocrine outcomes require ongoing follow-up.

Clinical Context

This landmark St. Jude series established the modern paradigm for pediatric ependymoma: maximal safe resection + conformal RT 59.4 Gy, omitting CSI for M0. It supported subsequent COG ACNS0121 design. Second-look surgery for STR is now routinely considered before RT.

References

References: Merchant TE et al, JCO 2009 (St. Jude series)