Combination of Stereotactic Radiosurgery with Immunotherapy: Is It a New Treatment Option for Brain Metastases?

Abstract

Brain metastases (BMs) represent the commonest intracranial tumours which occur approximately 30% of all adult patients presenting with solid cancers. The BMs do not only reduce the survival expectations but negatively alter the quality of life measures as well. For decades, surgery and whole-brain radiotherapy (WBRT) constituted the traditional treatment options with limited efficacy for the BMs. However, the unsatisfactory local control and ultimate survival outcomes led to a paradigm change, and stereotactic radiosurgery (SRS) has been executed as an alternative to surgery and WBRT or to augment the outcomes of each treatment when used in conjunction with them. In spite of the impressive improvements in the local control rates, yet the desired survival results were not achieved with SRS mainly due to the deaths ascribed to the extracranial systemic disease progression or unavoidably fatal distant brain recurrences. In this regard, as of late, numerous immunotherapeutics have been shown to improve the outcomes of various cancers, such as the locally advanced non-small-cell lung cancers. Recognizing the fact that the immunotherapy is becoming one of the indispensable components of standard treatment protocols for many tumour primaries, this review aimed to evaluate the efficacy and safety of the use of novel immunotherapeutics with standard SRS for BMs.