Gamma Knife surgery for subependymal giant cell astrocytomas

Abstract

Object The authors report their experience of using Gamma Knife surgery (GKS) in patients with subependymal giant cell astrocytoma (SEGA). Methods Over a 20-year period, the authors identified 6 patients with SEGAs who were eligible for GKS. The median patient age was 16.5 years (range 7–55 years). In 4 patients, GKS was used as a primary management therapy. One patient underwent radiosurgery for recurrent tumors after prior resection, and in 1 patient GKS was used as an adjunct after subtotal resection. The median tumor volume at GKS was 2.75 cm3 (range 0.7–5.9 cm3). A median radiation dose of 14 Gy (range 11–20 Gy) was delivered to the tumor margin. Results The median follow-up duration was 73 months (range 42–90 months). Overall local tumor control was achieved in 4 tumors (67%) with progression-free periods of 24, 42, 57, and 66 months. Three tumors regressed and one remained unchanged. In 2 patients the tumors progressed, and in 1 of these patients the lesion was managed by repeated GKS with subsequent tumor regression. The other relatively large tumor (5.9 cm3) was excised 9 months after GKS. The progression-free period for all GKS-managed tumors varied from 9 to 66 months. There were no cases of hydrocephalus or GKS-related morbidity. Conclusions Gamma Knife surgery may be an additional minimally invasive management option for SEGA in a patient who harbors a small but progressively enlarging tumor when complete resection is not safely achievable. It may also benefit patients with a residual or recurrent tumor that has progressed after surgery.