Radiosurgery in the treatment of brain metastases: critical review regarding complications

Stereotactic radiosurgery (SRS) has been described as an effective treatment option for brain metastases. In general, SRS has been indicated for the treatment of lesions smaller than 3 cm in maximum diameter and for lesions considered not surgically treatable, owing to the patient's clinical status or because the lesion was located in or near eloquent brain areas. In several studies, SRS has been associated with clinical and radiographic improvement of the lesions and has been compared with surgery as the modality of choice for brain metastases. Beyond the high rate of local disease control with SRS, the few complications that have been described occurred mainly in the acute post treatment period. Most publications have addressed the outcome and effectiveness of this treatment modality but have not critically analyzed long-term complications, steroid dependency, or results relating to specific brain locations. It is important to understand the radiobiologic effects of a well-demarcated high dose of radiation on the brain lesion, controlling the tumor growth and not causing significant alteration of the related brain region, especially in an area controlling eloquent function.