PTCT-02STEREOTACTIC LASER INTERSTITIAL ABLATION THERAPY FOR PEDIATRIC LOW-GRADE GLIAL NEOPLASMS

INTRODUCTION: Slowly growing deeply situated brain tumors in children pose a unique management dilemma. Considerations of watchful waiting, resection, chemotherapy and radiation therapy must be weighed carefully. With concerns over neurosurgical resection morbidity, the typical long-term ineffectiveness of chemotherapy and the feared sequelae of radiation therapy, our institution has chosen to manage select tumors using laser interstitial ablation via the stereotactic Visualase® system. METHODS: Five patients, ages 7, 8, 12, 15, 16 years had clinicoradiographic histories of slowly enlarging deep brain lesions characteristic of low-grade glial tumors. Locations included deep thalamus (2), cerebellar vermis (1), parieto-occiptal region (1) and a SEGA near a foramen of Monro (1). Options for management were discussed with each family, and laser ablation was decided upon. RESULTS: The patients were taken to the intraoperative MRI operating room for stereotactic needle biopsy and laser interstitial ablation during the same operation. Frozen section tissue analysis in all cases showed a low-grade glial tumor. Each patient underwent standard post-operative scanning, all showing evidence of lesional/peri-lesional signal change, a sign suggestive of desired zonal ablation injury to the tumor. Four patients had no evidence of post-procedure complications and were discharged several days post-procedure. One patient (cerebellar vermis) had significant post-ablation procedure ataxia and had evidence of incomplete ablation by virtue of tumor progression 16 months later, requiring a second ablation. None had evidence of concerning hemorrhage. All tumors were finalized as being low-grade glial (pilocytic) tumors. CONCLUSIONS: Stereotactic laser ablation therapy should be considered as an option in the management of select patients with deeply-situated glial tumors, in order to avoid potential serious neurosurgical morbidity via resection, or the dangers of irradiation. Continued long-term patient follow up will be needed in order to determine whether ablation therapy was successful. Further reporting on this technique by other investigators is suggested.