P11.05.B BENEFITS OF SODIUM FLUORESCEIN IN RESECTION OF BRAIN METASTASES

Abstract BACKGROUND For central nervous system (CNS) tumors, the use of intraoperative fluorophores can significantly improve resection in several ways. Although sodium fluorescein (Na-Fl) has been used for CNS tumors since the 1940s, experience and use of Na-Fl is relatively limited. To date, existing studies of Na-Fl assisted resection of brain metastases (BM) have involved a limited number of patients. MATERIAL AND METHODS Any patient at our institution who underwent resection of a cerebral lesion suspected of being BM between November 2023 and March 2025 received 200 mg 10% Na-Fl solution during induction of anaesthesia. The multidisciplinary tumor board confirmed the indication for any BM resection. A 560 nm filter microscope was used for intraoperative fluorescence guidance. Fluorescence patterns and extent of resection according to early postoperative cT1w MRI were recorded. Postoperative overall survival was determined for the available cases. RESULTS We enrolled 67 patients (28 females, mean age of 64 ±10 years) who underwent resection of at least 1 BM using intraoperative Na-Fl induced fluorescence. 43 patients had singular and 25 patients had multiple BM. Na-Fl fluorescence was positive in 94%, negative in 3% and not documented in another 3% of cases. Most common primary cancers were non-small cell lung cancer (43.3%), gastrointestinal carcinoma (13.4%), and malignant melanoma (10.4%). No negative side effects of Na-Fl were observed in any patient. Cost per patient was 12€. According to postoperative MRI, a gross total resection could be achieved in 64.2% of cases. Long-term data were available for 32 patients. Median follow-up time was 3.9 months (SD 3.8), and 6-month survival rate was 46.9%. Overall survival was statistically significantly different between patients with singular or multiple metastases (p<0.006, Log rank test). CONCLUSION Na-Fl facilitates intraoperative detection of BM. It appears to be safe, inexpensive and easy to use. However, Na-Fl also appears to accumulate in the adjacent areas of impaired blood-brain barrier. Further studies are warranted to investigate the benefits of using Na-Fl to improve the extent of resection.