Permanent I-125 brain stem implants in children

Area of Science:

• Pediatric neuro-oncology
• Radiation oncology
• Neurosurgery

Background:

• Brain stem gliomas are aggressive pediatric central nervous system (CNS) tumors.
• Stereotactic interstitial brachytherapy offers a targeted radiation approach.

Purpose of the Study:

• To evaluate the safety and efficacy of iodine-125 (I-125) implants for pediatric CNS tumors, particularly brain stem gliomas.
• To assess tumor control and survival rates following I-125 brachytherapy.

Main Methods:

• Retrospective analysis of 28 pediatric patients treated with I-125 implants between 1988 and 1997.
• Ten patients received stereotactic implantation in the brain stem region for glioma.
• Combined external beam radiation with fractionated stereotactic boost followed by I-125 interstitial therapy.

Main Results:

• No surgical complications were reported with catheter placement.
• Four patients died within 7-9 months; four survived for 5-38 months (median 10 months).
• Autopsies revealed progressive glioblastoma multiforme and necrosis; one patient with midbrain low-grade glioma (LGA) showed necrosis without tumor.

Conclusions:

• Stereotactic interstitial brachytherapy with I-125 is safe for pediatric brain stem tumors.
• Tumor control remains a significant challenge for high-grade brain stem gliomas despite high focal radiation doses.
• I-125 implants may have a role in managing pediatric CNS malignancies, warranting further investigation.