Adjuvant Stereotactic Radiosurgery for Anaplastic Ependymoma

Object: The purpose of this retrospective study is to evaluate the role of stereotactic radiosurgery using the Gamma Knife as an adjuvant to other modalities used in the treatment of malignant ependymomas of both children and adults and to assess its efficacy in terms of tumor control and overall survival. Method: Between 1987 and 1998, 22 patients in the age range of 1.5–65 years (mean age 22.3) with progressive anaplastic ependymoma were treated by stereotactic radiosurgery using the 201 source Co-60 Leksell Gamma Knife at the University of Pittsburgh. The irradiated tumor volume varied from 0.84 to 36.8 cm3 (mean 13.7). The median dose delivered to the tumor margin was 16.1 Gy (range 10–20), and the mean maximal dose was 32.2 Gy (range 20–40). The disease-free survival, the tumor control rate and the overall survival were recorded to evaluate the efficacy of radiosurgery. The median follow-up from radiosurgery was 21 months (range 4–84). Results: Median survival after radiosurgery was 2.2 years (46.6 ± 12.1% 5-year actuarial). Median survival from the initial diagnosis was 10.1 years (50.3 ± 12.5% at 5 years, 37.7 ± 14.4% at 10 years). Reduction or stabilization of the treated tumor was seen in 16 out of 22 (68%) patients. Forty-one percent of the patients eventually developed delayed distant cerebral recurrence outside the treated volume. The 5-year actuarial rates for local control and cranial control at any location were 62.3 ± 13.6% and 32.4 ± 10.8%, respectively. No complication occurred as a side effect of radiosurgery. Conclusion: For patients with locally recurrent or progressive anaplastic ependymomas, Gamma Knife stereotactic radiosurgery proved to be safe and effective as a salvage adjuvant therapy to achieve local tumor control and improve survival.