Gamma knife surgery for multiple hemangioblastomas

Abstract

OBJECT: The authors describe their experience in treating patients with hemangioblastoma, especially multiple lesions, with gamma knife surgery (GKS). METHODS: Nine patients with 84 hemangioblastomas underwent GKS between July 1992 and May 2003. Three patients harbored a single lesion and six patients had multiple lesions. Of the six patients with multifocal tumors, a diagnosis of von Hippel-Lindau disease had been established in five. In the patients with multiple lesions, the mean radiation dose delivered to the tumor margin was 16.6 Gy (range 12.8-29.75 Gy). The mean margin isodose was 60% (range 40-95%). Three of the 84 lesions failed to be controlled after a mean follow-up period of 4.3 years (range 8.6-141 months). One patient who had undergone two GKS treatments suffered delayed radiation-induced complications, and posterior fossa decompression and ventriculoperitoneal shunt insertion were required. CONCLUSIONS: To achieve tumor control and avoid morbidity, the surgeon should keep in mind minimizing field overlapping by using a small-diameter collimator or applying a steep dose gradient, and by accurate dose prescription.