Innovations in radiotherapy and advances in immunotherapy for the treatment of brain metastases

Radiotherapy for brain metastases has evolved tremendously over the past four decades, allowing for improved intracranial control of disease with reduced neurotoxicity. The main technological advance was provided by volumetric modulated arc therapy (VMAT), a computer-controlled delivery method that has opened the door for single-isocenter multi-metastases stereotactic radiosurgery (SRS) and hippocampal avoidance whole brain radiation therapy (HA-WBRT). Other notable advances have occurred in the combination of immune checkpoint inhibitors (ICI) and radiosurgery. When these two modalities are combined in the proper sequence (within 30 days from each other), it provides promising results in the treatment of intracranial metastases from melanoma. There is emerging evidence of a synergistic interaction between ICI and SRS, providing better intracranial tumor control and lengthening the survival of patients afflicted by this common complication of cancer.