Staged gamma knife radiosurgery for large critically located benign meningiomas: evaluation of a series comprising 20 patients

Klaus Haselsberger (1) , Thorsten Maier (1) , Karlheinz Dominikus (1) , Etienne Holl (1) , Senta Kurschel (1) , Petra Ofner-Kopeinig (1) , Frank Unger (1)

1 Medical University Graz

Objectives: This study investigates the efficacy of staged radiosurgical treatment for intracranial meningiomas exceeding 3 cm in diameter. Methods: Between April 1992 and May 2008 staged gamma knife radiosurgery (GKRS) was performed in 20 patients with large benign meningiomas. 14 patients had undergone surgery at least once. The patients' age ranged between 26 and 73 years (median 60.5 years). Tumour volumes measured between 13.6 and 79.8 cm3 (median 33.3), treatment volumes between 5.4 and 42.9 cm3 (median 19.0). Out of 41 treatments, the prescription dose at the tumour margin was 12 Gy for 33 treatments, 10 Gy for one, 14 Gy for four, 15 Gy for one, and 25 Gy for further two, respectively (median: 12 Gy to a marginal isodose of 45%). Median follow-up was 7.5 years. Results: Tumour control was achieved in 90% of our series (25 % tumour regression, 65 % stable size). 2 patients (10%) experienced tumour progression outlying the planning target volumes treated by an additional radiosurgical procedure. Thereafter, tumour volume decreased in one patient and remained stable in the second one. Clinically, 9 patients (45%) improved within the time of follow-up, 11 (55%) remained unchanged. Conclusion: Due to excellent tumour control at a low concomitant morbidity, staged SRS for meningiomas represents a safe treatment modality that can be recommended for meningiomas in critical locations either after incomplete surgery or as primary treatment for patients with significant co-morbidity.

Mots clés: gamma knife; meningioma; staged treatment; stereotactic radiosurgery

Klaus Haselsberger, Thorsten Maier, Karlheinz Dominikus, Etienne Holl, Senta Kurschel, et al.. Staged gamma knife radiosurgery for large critically located benign meningiomas: evaluation of a series comprising 20 patients. Journal of Neurology, Neurosurgery and Psychiatry, 2009, 80 (10), pp.1172. ⟨10.1136/jnnp.2008.156745⟩. ⟨hal-00552712⟩