Significance of 5-ALA-Guided Fluorescence in Resection of Invasive Intracranial Meningiomas: Findings from a Prospective Clinical Study
Background: In cases of intracranial meningiomas invading into surrounding tissues, determining the resection boundary can be challenging and often makes complete resection difficult. In such situations, the introduction of novel intraoperative techniques to identify infiltrative tumor components is desirable to improve the extent of tumor resection. Methods: A prospective clinical study was conducted on patients with intracranial meningiomas suspected of infiltration into the surrounding tissues. After completing the tumor resection under conventional white-light microscopy, intraoperative fluorescence diagnosis using 5-aminolevulinic acid (5-ALA) was performed to determine whether additional resection of the unintended residual tumor was feasible. Results: Intraoperative fluorescence diagnosis enabled additional resection of the residual tumor in 38.5% of the 13 enrolled cases and 45.5% of the 11 cases in which the tumor exhibited fluorescence positivity. Among the additional resected specimens, tumor infiltration was observed in all fluorescence-positive lesions of the bone and dura mater, whereas tumor cells were detected in only 33.3% of the fluorescence-positive areas in the adjacent brain parenchyma. Conclusions: Intraoperative fluorescence diagnosis using 5-ALA enhanced the extent of the resection of invasive meningiomas. Future large-scale studies are warranted to determine whether 5-ALA fluorescence diagnosis contributes to reducing tumor recurrence and improving overall survival in patients with invasive intracranial meningiomas.