Stereotactic radiosurgery for patients with recurrent intracranial ependymomas.

The objective of the study is to define the tumor control rate and complications associated with stereotactic radiosurgery (SRS) for patients with recurrent intracranial ependymoma. Retrospective review of 26 patients (49 tumors) having SRS between 1990 and 2008. Twenty-five patients (96 %) had undergone one or more craniotomies; one patient underwent SRS for a metastatic tumor after resection of a spinal ependymoma. Nineteen patients (73 %) had received cranial external beam radiotherapy (median dose, 54 Gy). Eight patients (31 %) were less than 18 years old. The median target volume was 2.2 cm(3) (range, 0.3-66.6); the median tumor margin dose was 18 Gy (range, 12-24). The median follow-up after SRS was 3.1 years (range, 3 months-13.1 years). The median overall survival after SRS was 5.5 years. The 1-year and 3-year survival rates were 96 and 69 %, respectively. Local tumor control (LC) was achieved in 33 of 49 lesions (67 %) with a median time to progression of 14.7 months (range, 2.9 months-11.2 years). The 1-year and 3-year progression-free survival rates were 80 and 66 %, respectively. The 1-year and 3-year LC rate was 85 and 72 %, respectively. On univariate analysis, higher tumor grade was associated with worse OS (grade 3-4, 27 % vs grade 2, 82 %, p = 0.04). Seven patients (27 %) had distant tumor progression and two patients (8 %) had symptomatic radiation necrosis after SRS. SRS for recurrent intracranial ependymoma provided good LC and may improve survival for patients with limited recurrent disease after prior treatment.