Stereotactic Radiosurgery for Intracranial Ependymomas

Abstract

To evaluate outcome predictors after stereotactic radiosurgery (SRS) in patients with recurrent or residual intracranial ependymomas, we compared tumor control, survival and complications with tumor grade, volume, age of patients, and imaging characteristics. We retrospectively reviewed records of consecutive 45 ependymoma patients who underwent SRS for 65 tumors. The median patient age was 25 years (range, 2–78 years). Forty-three patients had prior surgical resection of their ependymomas and two patients were diagnosed by stereotactic biopsy. Thirty-seven patients had failed prior fractionated radiation therapy (RT). Fourteen patients had progression despite both RT and chemotherapy. Thirty patients had low-grade ependymomas (40 tumors) and 15 patients had anaplastic ependymomas (25 tumors). The median radiosurgery target volume was 4.9 cc (range, 0.1–36.8 cc) and the median marginal dose was 15.0 Gy (range, 8–22 Gy). At an average of 31 months (range, 4–155 months), 27 patients died from metastases or disease progression. The overall survival after radiosurgery was 65, 41, and 38% at 1, 3 and 5 years, respectively. The progression-free survival after SRS at 1-, 3- and 5 years, respectively were 82, 52 and 52% for all grade ependymomas. Histological tumor grade was not significantly associated with better progression free survival (p = 0.725). Factors associated with an improved progression-free survival included smaller tumor volume and homogeneous tumor contrast enhancement. Adjuvant SRS provides another management option for patients with residual or recurrent ependymomas. Predictors of response include older age, smaller volume, lower grade, and homogeneous contrast enhancement.