Safety and efficacy of GammaTile intracranial brachytherapy implanted during awake craniotomy

Abstract

GammaTile intracranial brachytherapy (cesium-131 seeds) has demonstrated encouraging safety and local control results, and recently received Food and Drug Administration clearance for newly diagnosed and recurrent brain tumors. The authors present the first reported case of GammaTile intraoperative brachytherapy performed during an awake craniotomy. A 50-year-old man had a biopsy-proven, 2.8 cm left lateral frontal glioblastoma lesion nearing Broca's area on MRI. Despite several interventions (craniotomy, adjuvant chemoradiation, tumor treating fields) tumor progression occurred near the left parietal resection cavity. Re-resection was planned with awake craniotomy and language mapping. A preoperative planning session involving Radiation Oncology and Neurosurgery identified the area of the expected postoperative bed, and consequently five GammaTiles were ordered, each containing 4 cesium-131 3.5 U seeds. During surgery, tumor mapping and bipolar stimulation were performed while the patient spoke in complete sentences. Speech arrest occurred upon stimulation at the posterior edge of the gyrus, indicative of language cortex. Microsurgical maximal safe resection subsequently occurred, and areas at risk for residual/recurrence disease were determined in consultation with Radiation Oncology. Subsequently, Neurosurgery placed all five GammaTiles (20 cesium-131 seeds total) after which closure was completed and radioactive surveys of the room remained within state statue. Postoperative dosimetry yielded excellent coverage. The first reported case of GammaTile intraoperative brachytherapy during awake craniotomy supports the safety and feasibility of this treatment strategy. This case indicates that for patients with tumors adjacent to eloquent cortex, awake craniotomy can allow for custom implantation of intraoperative brachytherapy following maximum safe resection.