Therapeutic effect of linac-based stereotactic radiotherapy with micro-multileaf collimator for the treatment of patients with brain metastases

The purpose of this study was to assess the efficacy of linac-based stereotactic radiotherapy (SRT) with micro-multileaf collimator in patients with brain metastases. Data of 96 metastatic brain lesions of brain metastases in 60 patients treated by SRT between September 2003 and December 2005 were analyzed. The primary sites were lung (42 patients), breast (4 patients), colon (4 patients), and others (10 patients). In the treatment planning, planning target volume (PTV) was defined as enhanced lesion (=GTV) plus 3 mm margin. To the isocenters of PTV, total dose of 39-42 Gy with 3 fractions were delivered. The median survival after SRT was 15.1 months. The 1-year and 2-year survival rates were 56%, 36%, respectively. The local control rate was 86.2% with no serious adverse effects. After the treatment of SRT, new brain metastases and/or meningeal carcinomatosis were detected in approximately half of patients. SRT with a micro-multileaf collimator is an effective and safe modality in the treating patients with brain metastases. (author)