[First treatment for brain metastases by stereotactic radiosurgery]

Local control of brain metastases is better with first treatment by stereotactic radiosurgery than with radiosurgery for recurrence. We reported a retrospective analysis of the influence of clinical and technical factors on local control and survival after radiosurgery realised in first intention. From January 1994 to December 1997, 26 patients presenting with 43 metastases underwent radiosurgery. The median age was 61 years and the median Karnofsky index 70. Primary sites included: lung (12 patients), kidney (7 patients), breast (2 patients), colon (1 patient), melanoma (2 patients), osteosarcoma (1 patient), it was unknown for one patient. Seven patients had extracranial metastases. Twenty-one sessions of radiosurgery have been realized for one metastase, and 9 for two, three or four lesions. The median diameter was 21 mm and the median volume 1.8 cm3. The median peripheral dose to the lesion was 14 Gy, and the median dose at the isocenter 20 Gy. Forty-two metastases were evaluable for response analysis. The overall local control rate was 90.5% and the 1-year, 2- and 3-year actuarial rates were 85% and 75%. In univariate analysis, theorical radioresistance was significantly associated with better local control (100% versus 77%, p < 0.05). All patients were evaluable for survival. The median survival rate was 15 months. Four patients had a symptomatic oedema (RTOG grade II). Two lesions have required a surgical excision. In conclusion, low dose radiosurgery (14 Gy delivered at the periphery of metastasis) can be proposed in first intention for brain metastases, in particularly for theorical radioresistant lesions.