Tunable Technologies for the Glioma Tumor Microenvironment: A Comprehensive Review on Bench-to-Bedside Neurosurgical Advances.

Gliomas remain among the most treatment-resistant malignancies of the central nervous system. Glioblastoma (GBM), the most aggressive adult-type diffuse glioma, is associated with persistently poor survival despite maximal safe resection followed by chemoradiation. Gliomas do not grow in isolation. Work over the past twenty years has dismantled the older tumor-centric view of glioma biology, replacing it with a model in which malignant cells operate within a tumor microenvironment (TME) composed of immune, vascular, stromal, and neural elements that together govern disease behavior. What makes the glioma TME so difficult to treat is not just its composition of immune cells, vasculature, stroma, and neurons, but the fact that these elements are arranged unevenly across the tumor. Different regions harbor different cellular mixtures and signaling environments, and, as a result, different vulnerabilities to therapy. Cytoreduction has not lost its importance, far from it. However, the same surgical window now also serves a different purpose; it lets the surgeon see which tissue is biologically dangerous rather than just visually abnormal, locate the true edge of infiltration, and get therapeutics past a blood-brain barrier (BBB) that has historically locked them out of the brain. This review examines two technology domains, including: (1) optical theranostics (5-aminolevulinic acid fluorescence-guided surgery, fluorescein-guided visualization, Raman spectroscopy, and stimulated Raman histology); and (2) blood-brain barrier disrupting technologies. The direction they collectively point toward is a version of glioma surgery that is guided less by anatomy and more by the biology of the tumor itself.