Complications of stereotactic radiosurgery in patients with brain metastases: Considerations for deep and functional brain tumor locations

There is a widely held assumption that morbidity associated with stereotactic radiosurgery (SRS) is less common than that associated with its neurosurgical counterpart, and that SRS can be performed in any brain location regardless of depth or regional function. A literature review revealed an inadequate representation, description, and analysis of brain metastasis locations, including eloquent or deep-seated ones as a predictor of SRS-related complications. Most published series either do not report location or provide location data without a clear correlation with complications. A preliminary review of our experience at The University of Texas M. D. Anderson Cancer Center showed that complications were more frequent in treating lesions located in eloquent brain regions than in other brain areas. Among eloquent locations, complications were more frequent with tumors located in the motor or sensory centers, or the brainstem. We propose a critical examination of the notion of safety of SRS in eloquent or deep-seated brain locations based on the paucity of publications investigating the issue.