AIMS There is controversy in published studies regarding the role of repeat whole brain radiation (WBRT) for previously irradiated brain metastases. The aim of our retrospective study was to document the practice at Princess Margaret Hospital with respect to the re-irradiation of patients with progressive or recurrent brain metastatic disease after initial WBRT.    MATERIALS AND METHODS A comprehensive computerised database was used to identify patients treated for brain metastases with more than one course of WBRT between 1997 and 2003. Seventy-two patients were treated with WBRT for brain metastases and retreated with WBRT at a later date. The records of these patients were reviewed.   
 RESULTS The median age was 56.5 years. The most common primary sites were lung (51 patients) and breast (17 patients). The most frequent dose used for the initial radiotherapy was 20 Gy/5 fractions (62 patients). The most common doses of re-irradiation were 25 Gy/10 fractions (22 patients), 20 Gy/10 fractions (12 patients), 15 Gy/5 fractions (11 patients) and 20 Gy/8 fractions (10 patients). Thirty-one per cent of patients experienced a partial clinical response after re-irradiation, as judged by follow-up clinical notes; 27% remained stable; 32% deteriorated after re-irradiation. Patients who had Eastern Cooperative Oncology Group performance status 0-1 at the time of retreatment lived longer. In responders, the mean duration of response was 5.1 months. The median survival after re-irradiation was 4.1 months. One patient was reported as having memory impairment and pituitary insufficiency after 5 months of progression-free survival.   
 CONCLUSION Repeat radiotherapy may be a useful treatment in carefully selected patients. With increased survival and better systemic options for patients with metastatic disease, more patients may be candidates for consideration of repeat WBRT for recurrent brain metastases, but prospective studies are needed to more clearly document their outcomes.
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