Stereotactic radiosurgery for pilocytic astrocytomas part 2: outcomes in pediatric patients.

To assess outcomes after stereotactic radiosurgery (SRS) for newly diagnosed or recurrent pilocytic astrocytomas in pediatric patients. Fifty patients (28 male and 22 females) with juvenile pilocytic astrocytomas (JPA) underwent Gamma knife SRS between 1987 and 2006. The median patient age was 10.5 years (range, 4.2-17.9 years). Three patients had failed prior fractionated radiation therapy (RT) and two had failed RT and chemotherapy. The median radiosurgery target volume was 2.1 cc (range, 0.17-14.4 cc) and the median margin dose was 14.5 Gy (range, 11-22.5 Gy). At a median follow-up of 55.5 months (range 6.0-190 months), one patient died and 49 were alive. The progression free survival after SRS (including tumor growth and cyst enlargement) for the entire series was 91.7, 82.8 and 70.8% at 1, 3 and 5 years, respectively. Stereotactic radiosurgery for pediatric pilocytic astrocytomas should be considered when resection is not feasible, or if there is an early recurrence. The best response was observed in small volume residual solid tumors.