RTHP-09. SINGLE INSTITUTION’S EXPERIENCE FOR PEDIATRIC INTRACRANIAL EPENDYMOMA TREATED WITH ADJUVANT RADIOTHERAPY

Abstract

Abstract PURPOSE To investigate long term outcomes of pediatric intracranial ependymoma treated with maximal safe resection followed by radiotherapy in single institution. METHODS Between 1983 and 2016, 42 pediatric patients received adjuvant radiotherapy after surgery. There were 19 and 23 grade II and III ependymomas, and total resection could be performed in 50% of patients. There were 4 patients with initial leptomeningeal seeding, and craniospinal irradiation (CSI) was the component of adjuvant treatment in 5 patients including them. Local radiotherapy (median 54 Gy (range, 45–60 Gy) was performed in all the rest patients excluding three with whole-brain radiotherapy. RESULTS With a median follow-up of 89 months, 14 patients (33%) experienced recurrences after radiotherapy (m/c: intracranial, 79%, all within tumor bed). The 5- and 10-year progression-free survival (PFS) rates were 70% and 63%, and overall survival (OS) rates were 85% and 78%, respectively. The recurrence rates were significantly higher in patients younger than 3 years (64% vs. 23%, p = 0.024) or with subtotal resection (STR) (52% vs. 15%, p = 0.009). In multivariate analyses, age and STR were significant factors for PFS (p = 0.007 and 0.028, respectively). There was no independent prognostic factor for OS on multi-variate analysis. Fourteen patients experienced recurrence. Among them, all of 6 grade II cases showed local recurrence. Four grade II cases (67%) underwent aggressively salvage treatments such as resection, stereotactic radiosurgery were still under observation. However, 75% of 8 grade III recurrent cases were expired, despite aggressive salvage treatments. All 3 patients with seeding recurrent were grade III and died from disease. CONCLUSION Local adjuvant radiotherapy showed favorable survival in pediatric ependymoma. Even if recurrence occurs, aggressive salvage treatment would be needed for grade II ependymoma.