Endoscope-enhanced fluorescence-guided microsurgery increases survival in patients with glioblastoma.

[PURPOSE] Extent of resection (EOR) predicts progression-free survival (PFS) and may impact overall survival (OS) in patients with glioblastoma. We recently demonstrated that 5-aminolevulinic acid-(5-ALA)-fluorescence-enhanced endoscopic surgery increase the rate of gross total resection. However, it is hitherto unknown whether fluorescence-enhanced endoscopic resection affects survival.

[METHODS] We conducted a retrospective single-center analysis of a consecutive series of patients who underwent surgery for non-eloquently located glioblastoma between 2011 and 2018. All patients underwent fluorescence-guided microscopic or fluorescence-guided combined microscopic and endoscopic resection. PFS, OS, EOR as well as clinical and demographic parameters, adjuvant treatment modalities, and molecular characteristics were compared between microscopy-only vs. endoscopy-assisted microsurgical resection.

[RESULTS] Out of 114 patients, 73 (65%) were male, and 57 (50%) were older than 65 years. Twenty patients (18%) were operated on using additional endoscopic assistance. Both cohorts were equally distributed in terms of age, performance status, lesion location, adjuvant treatment modalities, and molecular status. Gross total resection was achieved in all endoscopy-assisted patients compared to about three-quarters of microscope-only patients (100% vs. 75.9%, p=0.003). The PFS in the endoscope-assisted cohort was 19.3 months (CI95% 10.8-27.7) vs. 10.8 months (CI95% 8.2-13.4; p=0.012) in the microscope-only cohort. OS in the endoscope-assisted group was 28.9 months (CI95% 20.4-34.1) compared to 16.8 months (CI95% 14.0-20.9), in the microscope-only group (p=0.001).

[CONCLUSION] Endoscope-assisted fluorescence-guided resection of glioblastoma appears to substantially enhance gross total resection and OS. The strong effect size observed herein is contrasted by the limitations in study design. Therefore, prospective validation is required before we can generalize our findings.