MRI-guided laser interstitial thermal therapy for the treatment of low-grade gliomas in children: a case-series review, description of the current technologies and perspectives.

BACKGROUND: Pediatric low-grade gliomas (LGGs) account for approximately half of all pediatric central nervous system tumors. The low-grade gliomas' first line of treatment is gross total resection. However, when gross total resection is not possible, options for adjuvant therapy are limited. MRI-guided laser ablation (magnetic resonance-guided laser interstitial thermal therapy (MRgLITT)) offers a new option for treatment in selected cases. We present a description of the current MRgLITT technology and an exemplary case-series review of our experience in its use in LGGs.

CASE DESCRIPTION: A 19-month-old male was referred to the pediatric neurosurgery clinic with an incidental left temporal lesion discovered on a prenatal ultrasound. An MRI of the brain revealed a diffuse mesial temporal lesion. Electroencephalogram (EEG) showed generalized activity arising from the lesion. The patient underwent a navigation-guided biopsy then, two bolts were secured to the skull, and laser ablation was performed with intraoperative MR guidance. Pathology was consistent with ganglioglioma. Follow-up images 13 months after ablation showed a significant volumetric reduction in size of the tumor.

DISCUSSION: It is important to achieve maximal resection of low-grade gliomas in children, lessening the need for adjuvant chemotherapy and radiotherapy, while minimizing the length of hospital stay and disruption to the child's life. Of our nine LGGs patients treated with this technology, six had undergone previous surgery and MRgLITT proved itself to be a safe surgical treatment option to achieve further cytoreduction. While most of the cases are pilocytic astrocytomas, the location of the tumors was surgically challenging. Eight of the nine cases required a single trajectory-laser-while our case example requires two lasers. Only a case of a midbrain-thalamic tumor presented a post-ablation significant brain edema as perioperative complication [1]. Eight of the nine tumors did not require any coadjuvant therapy or further surgical treatment to date.

CONCLUSION: MRIgLITT is a successful option for treatment for selected de novo or recurrent low-grade gliomas in children. It can be combined with other therapies offering the advantages of a minimally invasive procedure. LITT may be added to the current pediatric neuro-oncology protocols, but larger prospective series are needed to show the effectiveness of LITT and to standardize indications and protocols.