LINAC radiosurgery in skull base meningiomas.

LINAC radiosurgery has provided increasing access and changed treatment strategies in patients with benign skull base meningiomas in recent years. From January 1996 to January 2003, 37 patients with skull base meningiomas were treated with LINAC radiosurgery. A combination of the University of Florida system and the X Knife System, developed by Radionics, was used in all patients. Eight patients were treated by microsurgical resection before radiosurgery, in two patients tumor recurrence was treated and in 29 patients LINAC radiosurgery was the initial treatment procedure. The median treatment volume was 5.9 mL (0.7 to 22 mL) and the median given dose was 14.6 Gy (12.8 to 18 Gy) prescribed to the 80 percent isodose line. The follow-up period is between 12 and 96 months, median 66 months. 12 patients (32.4 %) showed a significant reduction in tumor size, in 11 patients (29.7 %) there was significantly less contrast enhancement and in 13 patients (35.1 %) the skull base meningioma was without any change. In one patient (2.8 %) there was tumor growth 48 months after radiosurgery, so the tumor control rate was 97.2 %. Two patients (5.6 %) showed neurological worsening after radiosurgery, whereas the symptoms were transient in one patient. LINAC radiosurgery offers us an effective treatment modality and changes treatment strategies in skull base meningiomas towards a less aggressive surgical approach. By combining microsurgery and radiosurgery we can achieve high tumor control rates with an acceptable low morbidity and a high level of quality of life.