FLUORESCEIN-GUIDED SURGERY FOR RESECTION OF MALIGNANT GLIOMAS

Introduction: Fluorescein is widely used as a fluorescent tracer for many applications. Its capability to accumulate in cerebral areas with blood-brain barrier damage makes it an ideal dye for intraoperative visualization of high-grade gliomas (HGG). This study presents a new fluorescein-guided technique to remove HGG with a dedicated filter on the surgical microscope (FLUOGLIO trial). Methods: The FLUOGLIO study is a prospective phase II-trial to evaluate safety and obtain initial indications about efficacy of fluorescein-guided surgery for HGG. Since September 2011, 24 patients (age range 45-74 years) were enrolled in the study. Fluorescein was intravenous injected after intubation (5-10 mg/Kg). Tumor was removed with microsurgical technique and fluorescence visualization by BLU400 or YELLOW560 filters on the Pentero microscope (Carl Zeiss, Germany). Degree of tumor resection was calculated on an early (within 72 hours of surgery) postoperative MRI. In 11 patients, biopsies were performed at the tumor margin in order to evaluate sensitivity and specificity of fluorescein in tumor tissue identification. The study was approved by our Ethical Committee and registered on the European Regulatory Authorities website (EudraCT No. 2011-002527-18) Results: Median pre-operative tumor volume was 33.1 cm3 (1.3-87.8 cm3). No adverse reaction related to the administration of fluorescein was registered. Contrast-enhanced tumor was completely removed in 83% of the patients on early postoperative MRI. The remaining patients had a mean tumor resection of 92.6%. Median follow-up was 12 months. The biopsies at the tumor margins gave a preliminary estimation of sensitivity and specificity of fluorescein in identifying tumor tissue of 95% and 86% respectively. Conclusion: The presented data suggest that fluorescein-guided technique with a dedicated filter on the surgical microscope is safe and allows a high-rate of complete resection of HGG at the early post-operative MRI.