Gamma Knife surgery for subependymal giant cell astrocytomas. Clinical article

The authors report their experience of using Gamma Knife surgery (GKS) in patients with subependymal giant cell astrocytoma (SEGA).

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 cm(3) (range 0.7-5.9 cm(3)). A median radiation dose of 14 Gy (range 11-20 Gy) was delivered to the tumor margin.

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 cm(3)) 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.

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.