Radiosurgery in the management of brain metastasis: a retrospective single-center study comparing Gamma Knife and LINAC treatment


Journal of Neurosurgery, Ahead of Print. OBJECTIVE The authors present a retrospective analysis of a single-center experience with treatment of brain metastases using Gamma Knife (GK) and linear accelerator (LINAC)–based radiosurgery and compare the results. METHODS From July 2010 to July 2012, 63 patients with brain metastases were treated with radiosurgery. Among them, 28 (with 83 lesions) were treated with a GK unit and 35 (with 47 lesions) with a LINAC. The primary outcome was local progression–free survival (LPFS), evaluated on a per-lesion basis. The secondary outcome was overall survival (OS), evaluated per patient. Statistical analysis included standard tests and Cox regression with shared-frailty models to account for the within-patient correlation. RESULTS The mean follow-up period was 11.7 months (median 7.9 months, range 1.7–32 months) for GK and 18.1 months (median 17 months, range 7.5–28.7 months) for LINAC. The median number of lesions per patient was 2.5 (range 1–9) in the GK group and 1 (range 1–3) in the LINAC group (p < 0.01, 2-sample t-test). There were more radioresistant lesions (e.g., melanoma) and more lesions located in functional areas in the GK group. Additional technical reasons for choosing GK instead of LINAC were limitations of LINAC movements, especially if lesions were located in the lower posterior fossa or multiple lesions were close to highly functional areas (e.g., the brainstem), precluding optimal dosimetry with LINAC. The median marginal dose was 24 Gy with GK and 20 Gy with LINAC (p < 0.01, 2-sample t-test). For GK, the actuarial LPFS rate

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