Combined Stereotactic Radiosurgery and Immune Checkpoint Inhibitors for the Treatment of Brain Metastasis

Metastasis of solid tumors to the brain occurs in about 30% of cases. Surgery and whole-brain radiotherapy have been the standard treatments with very limited success rates. As a result of the unsatisfactory local control and long-term survival outcomes, stereotactic radiosurgery has been used as an alternative to surgery and whole-brain radiotherapy, or to improve the outcomes in conjunction with other treatments. However, stereotactic radiosurgery does not produce the desired survival results despite the striking increases in local control rates, primarily because of deaths attributed to extracranial systemic disease progression or unavoidably fatal distant brain recurrences. Lately, immunotherapy has become a part, or mainstay, of treatment algorithms for many cancer types. Several authors have proposed the integration of stereotactic radiosurgery and immunotherapy for the treatment of brain metastasis. This chapter evaluates the efficacy and safety of combining novel immunotherapeutics with traditional stereotactic radiosurgery for the treatment of brain metastasis.