Drug delivery methods such as nanoparticles, convection enhanced delivery, focused ultrasound, intranasal delivery, and intra-arterial delivery have not yet led to a significant increase in survival for most patients with a malignant primary brain tumor.

Blood–brain barrier disruption is heterogeneous within and between primary brain tumors in both adult glioblastoma and pediatric brain tumors.

A multimodal drug delivery approach might be more effective than a single drug delivery method.