The Significance of Tumor Location for Gamma Knife Treatment of Meningiomas

We conducted this retrospective review to evaluate the influence of tumor location on the outcome of Gamma Knife treatment (GKT) for meningiomas. Patient charts from 1995 to 2001 of the Gamma Knife Center Zurich, Switzerland, were reviewed. Of 81 patients, 23% had parasagittal or convexity meningiomas (PCM), 62% had skull base meningiomas (SBM), and 15% had posterior fossa meningiomas (PFM). Tumor control was achieved in 95% of PCM, 92% of SBM, and 100% of PFM. Neurological deficits were present in 5% of patients with PCM before and following GKT, in 62% of patients with SBM before GKT and in 46% following GKT, and in 17% of patients with PFM before and following GKT. We conclude that tumor location has an influence on tumor control and outcome. Deep and small tumors seem to be associated with better tumor control and less complications. Neurological deficits tend to resolve in deep tumors following GKT.