Reevaluating surgery and re-irradiation for locally recurrent pediatric ependymoma-a multi-institutional study.

Area of Science:

• Pediatric Oncology
• Radiation Oncology
• Neuro-oncology

Background:

• Ependymoma is a common primary brain tumor in children.
• Locally recurrent ependymoma presents a significant treatment challenge.
• Optimizing re-treatment strategies is critical for improving patient outcomes.

Purpose of the Study:

• To evaluate the impact of surgical resection extent and re-irradiation parameters on survival in pediatric patients with recurrent ependymoma.
• To analyze the relationship between gross total resection (GTR) and progression-free survival (PFS) and overall survival (OS).
• To compare the effectiveness of craniospinal irradiation (CSI) versus focal radiotherapy (RT2) in the re-treatment setting.

Main Methods:

• Retrospective review of 35 children with locally recurrent ependymoma treated with a second course of fractionated radiotherapy (RT2) across 6 North American cancer centers.
• Analysis of surgical resection extent (GTR) prior to RT1 and RT2.
• Comparison of PFS and OS based on RT2 modality (CSI vs. focal) and GTR status.

Main Results:

• Gross total resection (GTR) prior to RT2 was associated with improved PFS (HR 0.41, P=0.04) and OS benefit for infratentorial tumors (HR 0.26, P=0.03).
• Median PFS was superior with craniospinal irradiation (CSI) RT2 (not reached) compared to focal RT2 (56.9 months; P=0.03).
• Distant failures were rare after CSI RT2, and local failures were more common in patients with sub-GTR prior to RT2.

Conclusions:

• Maximal safe resection, aiming for GTR, is recommended for recurrent pediatric ependymoma.
• Craniospinal irradiation (CSI) re-irradiation should be considered for eligible patients.
• Treatment decisions should involve a thorough discussion of potential side effects.