Stereotactic radiosurgery (SRS) alone has become one of the treatment options for patients with 1-4 metastases as the detrimental effects of whole brain radiation therapy on neurocognition and quality of life are becoming well known. Multiple randomized control trials also failed to show overall survival benefit of adding whole brain radiation therapy to SRS. However, the role of SRS in multiple brain metastases, especially those with ≥ 4 tumors, remains controversial. The literature is emerging, and the limited evidence suggests that the local control benefit is independent of the number of metastases, and that patients with more than four brain metastases have similar overall survival compared to those with 2-4 tumors. This review aims at summarizing the current evidence of SRS for multiple brain metastases, divided into limited (2-3) and multiple (≥ 4) lesions. It also reviews the technical aspects and cost-effectiveness of SRS.
Keywords: brain metastases; gamma knife system; neurocognitive function; stereotactic radiosurgery; whole brain radiation therapy.