Fluorescein Sodium in the Surgical Treatment of Recurrent Glioblastoma Multiforme

BACKGROUND: Glioblastoma multiforme (GBM) is the most common primary brain tumor and has a high recurrence rate. Maximizing the extent of resection (EOR) in recurrent GBM has proved to be the cornerstone of neurosurgical retreatment. The development of surgical microscopes fitted with fluorescein-specific filters has facilitated fluorescein-guided microsurgery and the identification of tumor tissue. Use of fluorescein sodium (FL) in primary high-grade glioma resection has shown promising results. Here, we present our experience with FL and the dedicated surgical microscope filter YELLOW 560 nm in 106 patients with recurrent GBM. METHODS: A total of 106 patients with recurrent GBM were included (53 women, 53 men; mean age, 53 years). A total of 5 mg/kg bodyweight of FL was intravenously injected approximately 45 minutes before craniotomy. A YELLOW 560 nm filter (PENTERO 900 [Carl Zeiss Meditec, Oberkochen Germany]) was used for microsurgical tumor resection and resection control. Surgical reports were reviewed regarding the degree of fluorescent staining. Postoperative magnetic resonance images were examined within 48 hours after surgery regarding the EOR and postoperative course regarding neurologic outcome, complications, and any adverse events. RESULTS: Bright fluorescent staining was present in all patients, which markedly enhanced tumor visibility and was deemed helpful for tumor resection. Seventeen patients (16%) showed residual tumor tissue on postoperative magnetic resonance imaging (MRI). Therefore, gross total resection was achieved in 89 patients (84%). No adverse events were registered postoperatively. CONCLUSIONS: FL and YELLOW 560 nm are readily available methods for fluorescence-guided tumor resection, similar to contrast enhancement in T1-weighted MRI. FL may improve resection in recurrent GBM with minimal risk, and tumor margins are clearly visualized. FL and the YELLOW 560 nm filter are safe and feasible tools for safe maximal resection of recurrent glioblastoma.