EPEN-13. PATTERN OF RELAPSE IN POSTERIOR FOSSA EPENDYMOMA GROUP A

Abstract PURPOSE/OBJECTIVE Posterior fossa ependymoma group A (PF-EPN-A) is a poor prognostic subgroup, predominantly seen in infants and young children. Among all ependymomas, most of the recurrences are patients with PF-EPN-A subgroup. Despite advances neurosurgery postoperative adjuvant therapy, management these tumors remains challenging, recurrence occurs over 50% cases. In this study, we aimed to evaluate pattern relapse PF-EPN-A. MATERIALS AND METHODS The clinical features, treatment strategies patterns diagnosed treated at Hospital for Sick Children, Toronto have been evaluated retrospectively. RESULTS Seventy-five were from 01 June 1996 2022. All surgery +/- focal radiation chemotherapy after diagnosis. Out 75 patients, 38 (50.6%) had recurrent disease. Twenty-three (60.5%) local while 15 (40.5) experienced distant relapse. 23 who relapse, only 8 (34%) developed gross total resection (GTR). Other either subtotal (STR) or near (nTR). 10 (66%) GTR. Time was mean 32 months (11-132 months) GTR 24 (1-98 STR /nTR. CONCLUSIONS modern approach (more aggressive early conformal radiotherapy) changed classical dogma that “nearly relapses local’’ series. This study supported importance also demonstrated tends recur more on sites rather than locally when initial surgical intervention