SURG-27. Prolonged tumor control in multifocal glioblastoma through a staged, multimodal therapeutic approach – a case report

Abstract Multicentric glioblastoma, representing nearly 17% of glioblastoma cases, carries an aggressive phenotype with median survival of less than one year. Given the widespread, infiltrative nature of the disease, complete resection is rarely possible, and initial management frequently involves surgical biopsy/debulking followed by adjuvant chemoradiation. We report a case of a 56-year-old female who presented with progressive right-hand numbness/weakness and was diagnosed with three enhancing lesions (left frontal operculum, left pre-central gyrus, and right post-central gyrus) concerning for metastatic disease without systemic lesions. Needing symptomatic relief and pathologic diagnosis, the patient underwent awake craniotomy for gross total resection of the left-sided enhancing lesions for language and motor mapping. Postoperatively, the patient had temporary worsening of right-hand weakness, with progressive improvement in strength though persistent loss of dexterity. Pathology was consistent with IDH wild-type, MGMT-methylated glioblastoma (TERT mutant, EGFR amplification, EGFRvIII mutation, CDKN2A/CDKN2B deletion). The patient underwent concurrent temozolomide and radiation adjuvant therapy. Follow-up imaging three months postoperatively revealed progression of the right parietal lesion. The patient declined recommended craniotomy with motor mapping, so LITT guided by DTI and Fiber Tractography of the corticospinal tracts was performed, achieving near-total ablation. The patient remained at her neurologic baseline and pathology was consistent with residual tumor with tumor effect. Maintenance temozolomide was started and although tumor-treating fields (TTF) were recommended, the patient declined starting therapy until approximately 4 months post-LITT. No recurrence was detected by serial MRI in any of the lesions until 6 months post-LITT, wherein trace nodular enhancement without hyperperfusion was noted at the anterior aspect of the ablation cavity along the corticospinal tracts with planned serial monitoring. This case demonstrates the feasibility and prolonged control afforded by multimodal treatment of an aggressive glioblastoma subtype, highlighting the expanding role of minimally invasive LITT in patients who otherwise decline surgical intervention.