Role of stereotactic radiosurgery for multiple (>4) brain metastases

Stereotactic radiosurgery (SRS) is a very important treatment option for patients with brain metastases. Prospective data supports the use of SRS for patients with 1-4 brain metastases. Although whole brain radiation therapy (WBRT) has been an effective adjunct to SRS and surgery and has also provided effective palliation for many patients with brain metastases, the potential side effects especially neurocognitive function decline has increased the use of SRS alone even for patients with multiple (>4) brain metastases despite data that suggests that tumor progression is worse than the potential neurocognitive effects of WBRT. In addition, current stereotactic radiosurgery machines and techniques allow the delivery of SRS to multiple lesions in an efficient manner. As a result, the optimal management of multiple brain metastases (>4) is becoming more contentious given the lack of prospective data. Until further data is available, a multidisciplinary team of neurosurgeons, radiation oncologists, medical oncologists and medical physicists should work closely together to implement individualized treatment for patients with multiple brain metastases. This paper will review some of the institutional, multi-institutional and randomized trials of SRS for patients with brain metastases, and review the outcomes for patients with multiple (>4) brain metastases treated by SRS and the associated costs.