Rationale for intraoperative radiotherapy in glioblastoma

Glioblastoma is the most common and aggressive adult primary brain cancer. Despite multimodal therapy, it is associated with a survival of less than two years. Greater than 85% of recurrences occur within the original area of surgery and radiotherapy, suggesting a potential for improved local treatments. In addition to cancer cell invasion beyond surgical margins, a plethora of postinjury pro-proliferative stimuli are released from local healing brain, which both protect and nourish remaining cancer cells. This review compiles preclinical and clinical evidence for a dedicated treatment of both residual cancer cells and regional microenvironment using intraoperative radiotherapy (IORT).