CyberKnife stereotactic irradiation for metastatic brain tumors

BACKGROUND: The CyberKnife provides a new technique for performing frameless stereotactic irradiation. So far, few reports have been published on clinical outcomes obtained with the CyberKnife. This report summarizes our clinical experience with CyberKnife irradiation for metastatic brain tumors. MATERIALS AND METHODS: Seventy-seven lesions (48 patients) were evaluated and analyzed, and 66 lesions in 41 patients were treated with stereotactic radiosurgery (SRS). The prescribed dose was 9 to 30 Gy. RESULTS: Freedom from progression of the tumors was more likely with a prescribed dose of at least 24 Gy than with one of less than 20 Gy (p=0.0244; log-rank test). The CR (complete response) rate was significantly higher when D99 was at least 24 Gy (p=0.0045). There were no severe side effects. CONCLUSION: Stereotactic irradiation with the CyberKnife for metastatic brain tumors is effective and safe. D99 should be at least 24 Gy for CyberKnife SRS treatment.