P11.85.B LONG-TERM OUTCOME AFTER INCOMPLETE RESECTION OF INTRAMEDULLARY GRADE II EPENDYMOMAS WITHOUT ADJUVANT RADIOTHERAPY

Abstract

Abstract BACKGROUND Ependymomas are the most frequent intramedullary tumors in adults. While gross total resection is the aim of surgery, tumor infiltration might limit resection. In case of subtotal removal, the adjuvant management remains unclear. The aim of our study was to assess the need for adjuvant radiotherapy after incomplete resection of grade II intramedullary ependymomas (IME-II). MATERIAL AND METHODS We retrospectively reviewed all cases of IME-II operated in a single tertiary neurosurgical center from 2009 to 2018. Patients with anaplastic or myxopapillary ependymomas, and patients with a follow-up of less than 3 years were excluded. RESULTS We included 46 patients: 19 (41.3%) had gross total resection, 21 (45.7%) had subtotal resection and 6 (13%) had partial resection. None of the patients underwent adjuvant radiotherapy. Over a median follow-up of 79 months (range = 36-186), 7 patients presented a radiological tumor progression with a mean delay of 50.9 months (range =18-85), of which 2 were symptomatic (4.3%). Progression-free survival (PFS) was 90.1% at 5 years and 76.8% at 10 years. Extent of resection was the only significant risk factor for secondary tumor progression (p=0.012). 4 of the 7 patients with recurring IME-II were treated: 3 patients had a second surgery, leading to 2 GTR and 1STR, followed by radiotherapy in one case, and 1 patient underwent radiotherapy alone. CONCLUSION In this study, the rate of symptomatic progression and retreatment after incomplete resection of IME-II without adjuvant radiotherapy was low, supporting a conservative approach in such cases.