Immunotherapy and radiation in glioblastoma

Radiation therapy plays a central role in the management of glioblastoma. Although primarily thought of as modality to provide local tumor control through DNA damage, the capacity of ionizing radiation to modulate tumor immune response has long been recognized. The recent emergence of clinically active immunotherapies offers exciting potential for harnessing the immune modulatory effects or radiation through combinatorial strategies designed to enhance clinical outcomes. In this Review, we provide background describing the unique immune environment within the central nervous system, how ionizing radiation may modulate the tumor immune response, preclinical and clinical data testing the combination of radiation and immune modulating agents, and highlight some of the current challenges in extending these findings clinically.