gms | German Medical Science

Objective: Skull base meningiomas are benign tumors which are dreaded for their surgically hardly accessible location with respect to radical microsurgical resection. Treatment options of most of benign meningiomas arising from the skull base involve the so called "wait and see" strategy, microsurgery, debulking followed by radiosurgery or radiosurgery as first treatment option. We report on the efficacy of Gamma Knife radiosurgery (GKRS) for the treatment of cavernous sinus, pure petroclival and cerebello pontine angle meningiomas, comparing these major skull base subgroups with respect to imaging control and side effects.

Methods: From 15 participating centers, we performed a retrospective observational analysis of a cohort of 2172 benign meningiomas treated with GKRS. All were treated with Gamma Knife radiosurgery at least 5 years before assessment for this study. Clinical and imaging data were retrieved from each center and uniformly entered into a database by 1 author (A.S.). A comparative analysis is presented. All tumours with imaging follow-up shorter than 24 months were excluded from statistics.

Results: 2074 patients harbouring 2172 meningiomas treated in fifteen institutions recruited were evaluated. 1272 were cavernous sinus meningiomas 468 were pure petroclival meningiomas and the remaining 432 were located in the cerebello pontine angle. The median age was 54 years 56 years and 60,8 years for the three subgroups respectively. The median tumour volume was 7.90 ccm, 4.90 ccm and 4.10 ccm respectively. The median tumour margin dose to the 50% isodose line was 14.2 Gy, 13.9 Gy and 13.0 Gy respectively. The median cumulative imaging follow-up was 60 months. The detailed results from 1899 meningiomas (89%) were available for analysis. The actuarial control rate was 97.6% for CS meningiomas 97.1% for PC meningiomas and 98.3% CPA meningiomas at 5 years post GKRS. The permanent morbidity rate was 5.3%, 7.8% and 7,8% respectively for the three subgroups analyzed.

Conclusions: GKRS is a safe and not invasive method of treatment of deep located skull base meningiomas and the large number analyzed shows comparable results for the major subgroups investigated with a high imaging tumor control and low morbidity rate even in the medium to long-term.