J Neurol Surg A Cent Eur Neurosurg 2014; 75 - p78
DOI: 10.1055/s-0034-1383805

Tailored Radiosurgical Planning of Skull-Base Meningiomas in the Era of Gamma Knife Perfexion: A Prospective Series of 100 Consecutive Cases

C. Tuleasca 1, 2, 3, 4, L. Schwyzer 5, L. Schiappacasse 4, 6, M. Zeverino 7, R.-T. Daniel 1, 4, M. Levivier 1, 4
  • 1Centre Hospitalier Universitaire Vaudois (CHUV), Neurosurgery Service and Gamma Knife Center, Lausanne, Switzerland
  • 2Swiss Federal Institute of Technology (EPFL), Laboratory of Transmission Signal (LTS-5), Lausanne, Switzerland
  • 3Centre Hospitalier Universitaire Vaudois (CHUV), Medical Image Analysis Laboratory (MIAL), Lausanne, Switzerland
  • 4University of Lausanne, Faculty of Biology and Medicine, Lausanne, Switzerland
  • 5Kantonsspital Aarau, Neurochirurgische Klinik und Hirntumorzentrum, Lausanne, Switzerland
  • 6Centre Hospitalier Universitaire Vaudois (CHUV), Radiation Oncology Service, Lausanne, Switzerland
  • 7Centre Hospitalier Universitaire Vaudois (CHUV), Institute of Radiation Physics, Lausanne, Switzerland

Aims: Gamma Knife surgery (GKS) with Leksell Gamma Knife Perfexion® (LGK-PFX, Elekta Instruments, AB, Sweden) started in CHUV in July 2010. We review our series of meningiomas, focusing on those located at the skull-base, because of their challenging radiosurgical planning and risk of high morbidity and mortality associated with complete surgical removal.

Methods: We analyzed a total number of 155 cases (25% of our GKS activity), treated over a period of 3.5 years. Patient’s characteristics, as well as anatomical, clinical and dose planning parameters were prospectively collected in a dedicated case-report form.

Results: Hundred cases (64.5%) were skull-base meningiomas, with the following locations: 31 (20%) cavernous sinus and parasellar, 20 (12.9%) petro-clival, 23 (14.8%) petrous apex, 10 clinoid (6.5%), 5 (3.2%) olfactory groove, 3 (1.9%) cerebellopontine angle, 5 (3.2%) frontal base and 3 (1.9%) foramen magnum. The mean follow-up period was 1.1 years (0.3- 3.5). Twelve cases (7.7%) have been operated using a combined approach, with radiosurgery as a complementary treatment after initial planned subtotal surgical removal of the tumor, so as to avoid as much as possible morbidity and mortality associated with extended surgical resection. The mean marginal dose was 12.9 Gy (11-14). The mean maximal diameter was 24.8 mm (3.5-45). The mean target volume was 3.4 cc (0.14-12.5). The mean prescription isodose volume was 4.5 cc (0.26-15.2). The mean duration of GKS treatment was 85 minutes (31-144). Four patients had staged radiosurgery, because of the high tumor volume at the moment of treatment, and contra-indication to open surgery. Our preliminary neuroradiological follow-up shows 97% tumor control, with 30% shrinkage. No patient presented further clinical deterioration of pre-existing symptoms after GKS; furthermore, no new neurological deficit or complication occurred, during the follow-up period. Twenty percent of the symptomatic patients had clinical improvement after GKS.

Conclusions: Selection of the optimal strategy for these tumors still remain a matter of debate in the current literature, and depends on several factors like natural history, patient’s age, tumor size, symptoms, quality of life and also the possibility of using radiosurgery as first intention treatment. In our series, good conformity and selectivity were achieved with a high rate of clinical and radiological success in this early analysis.