Local radiotherapeutic management of ependymomas with fractionated stereotactic radiotherapy (FSRT)

Background: To assess the role of Fractionated Stereotactic Radiotherapy (FSRT) in the management of ependymomas. Methods: From January 1992 to July 2003, FSRT was performed in 19 patients with histologically confirmed ependymomas. The median age was 15 years, 5 patients were younger than 4 years of age. Twelve patients received FSRT as primary postoperative radiotherapy after surgical resection. In 6 patients irradiation of the posterior fossa was performed with a local boost to the tumor bed, and in 4 patients the tumor bed only was irradiated. In 7 patients FSRT was performed as re-irradiation for tumor progression. This patient group was analyzed separately. A median dose of 54 Gy was prescribed in a median fractionation of 5 x 1.8 Gy per week for primary RT using 6 MeV photons with a linear accelerator. For FSRT as re-irradiation, a median dose of 36 Gy was applied. All recurrent tumors were localized within the former RT-field. Results: The 5- and 10-year overall survival rates were 77% and 64%, respectively. Patients treated with FSRT for primary irradiation showed an overall survival of 100% and 78% at 3 and 5 years after irradiation of the posterior fossa with a boost to the tumor bed, and a survival rate of 100% at 5 years with RT of the tumor bed only. After re-irradiation with FSRT, survival rates of 83% and 50% at 3- and 5 years, respectively, were obtained. Progression-free survival rates after primary RT as compared to re-irradiation were 64% and 60% at 5 years, respectively. FSRT was well tolerated by all patients and could be completed without interruptions due to side effects. No severe treatment related toxicity > CTC grade 2 for patients treated with FSRT could be observed. Conclusion: The present analysis shows that FSRT is well tolerated and highly effective in the management of ependymal tumors. The rate of recurrences, especially at the field border, is not increased as compared to conventional radiotherapy consisting of craniospinal irradiation and a local boost to the posterior fossa.