gms | German Medical Science

Objective: We evaluated the effectiveness and toxicity of radiosurgical treatment for benign skull base meningiomas in 400 patients with a long-term follow-up of 55–12 years in order to define the role of gamma knife radiosurgery as a treatment option.

Methods: In total more than 1000 patients with meningiomas were treated with gamma knife radiosurgery (GKRS) as primary or adjunctive treatment at our department between 1992 and 2010. Of these patients 400 had a minimum follow-up of 60 months (range 60–150 months). 230 patients were treated with a combination of microsurgical resection and GKRS, 170 patients with GKRS as the primary treatment. 18 patients underwent staged GKRS for meningiomas exceeding 3 cm in diameter. The median tumour volume was 6.2 cm³ (range from 0.31–91 cm³). Margin doses applied to the tumour ranged from 7–26 Gy (median 12 Gy). Clinical and radiographic evaluations were performed 6-monthly for the first five years and then yearly afterwards.

Results: The 5 and 10 year progression-free survival rates were 89 and 75%, respectively. In 85% the tumour volume was unchanged or had decreased at the time of last follow-up. 18 patients suffered from new cranial nerve deficits after GKRS. 46% of patients experienced clinical improvement while 49% remained stable. 5% showed new neurological deficits. Repeated microsurgical resection was performed in 9 patients following GKRS.

Conclusions: GKRS is a safe and effective treatment either as a primary or adjunctive treatment of selected patients. For large-sized tumours low-dose radiosurgery and/or staged radiosurgical treatment is acceptable to prevent tumour progression.