Gamma Knife Radiosurgery of Brainstem Gliomas

Summary

From August 1992 until December 1999 Gamma Knife radiosurgery (GKRS) was applied to 21 patients (male to female ratio 14:7) with brainstem gliomas. Patient’s median age was 23 years (8–56 years). All tumours were histologically confirmed by biopsy or open surgery: 12 low-grade gliomas and 9 malignant growths. Two lesions were located primarily in the medulla, 12 in the pons and 7 in the midbrain. A median dose of 12 Gy (9–20 Gy) was applied to the tumour margin by the median isodose of 45%. Prior to radiosurgery 4 patients were treated by conventional radiotherapy, 1 had radiotherapy and chemotherapy, 1 patient underwent chemotherapy, and 1 patient was shunted due to hydrocephalus.

Neuroimaging controls (MR, CT) were obtained from 19 patients. The median interval between radiosurgery and the last neuroimaging control was 11.8 months (1–74 months). Neuroimaging depicted tumour progression in 2 patients, stable disease in 10 patients and regression in 3 cases. Follow-up periods ranged between 3 and 99 months (median 29 months). The neurological state improved in 5 patients. Microsurgical cyst fenestration was performed in 1 patient after GKRS, shunting procedure was necessary for 2 patients. Nine patients died unrelated to radiosurgery within 3 to 45 months (median 20.7 months).

GKRS is an effective treatment modality for brainstem gliomas with satisfying tumour control and functional outcome.