Current status of intratumoral therapy for glioblastoma

With emerging drug delivery technologies becoming accessible, more options are expected to become available to patients with glioblastoma (GBM) in the near future. It is important for clinicians to be familiar with the underlying mechanisms and limitations of intratumoral drug delivery, and direction of recent research efforts. Tumor-adjacent brain is an extremely complex living matrix that creates challenges with normal tissue intertwining with tumor cells. For convection-enhanced delivery (CED), the role of tissue anisotropy for better predicting the biodistribution of the infusate has recently been studied. Computational predictive methods are now available to better plan CED therapy. Catheter design and placement-in addition to the agent being used-are critical components of any protocol. This paper overviews intratumoral therapies for GBM, highlighting key anatomic and physiologic perspectives, selected agents (especially immunotoxins), and some new developments such as the description of the glymphatic system.