RADT-43. LONG TERM OUTCOMES OF PEDIATRIC AND ADULT CENTRAL NEUROCYTOMA—THE ROLE OF SALVAGE RADIOTHERAPY AND CONSERVATIVE MANAGEMENT

Abstract

Abstract INTRODUCTION Central Neurocytoma (CN) is a rare, WHO grade 2 brain tumor that predominantly affects young adults. Gross total resection (GTR) is often curative for CN, but the optimal treatment paradigm following subtotal resection (STR) and or scarcer pediatric cases has yet to be established—including the role of radiation therapy (RT). Herein, we reviewed the long-term outcomes of CN patients at our institution. METHODS Patients between the years 2001 and 2021 with a pathologic diagnosis of CN were reviewed. Demographic, treatment, and tumor characteristics (histopathological and molecular) were recorded. Recurrence free survival (RFS) and overall survival (OS) were calculated according to the Kaplan Meier-method. Post-RT tumor volumetric regression analysis was performed. RESULTS Seventeen adults (≥ 18 years old) and 5 children (< 18 years old) met the criteria for data analysis (n = 22). With a median follow-up of 6.9 years (range: 1.2-42.8 years), there was zero tumor-related mortality. Patients who received STR and/or had atypical tumors (criteria = Ki-67 >4%) experienced decreased RFS compared to those who received GTR and/or were without atypical tumors. RFS at 5 years was 67% for typical CNs and 22% for atypical CNs. Every pediatric tumor was atypical and 3/5 recurred within 5 years. Salvage RT following tumor recurrence led to 100% tumor control, with no further recurrences (median post-RT follow-up = 5.79 years); volumetric analysis for 3 recurrent tumors (8.59 cumulative years of serial scans) revealed an ~80% reduction in tumor (range: 76.3%-81.1%), at a mean rate of 2.49% per month. CONCLUSION We provide encouraging evidence that (1) CNs have limited long-term risk of tumor-related mortality and (2) RT after tumor recurrence conveys strong long-term tumor control, including for potentially more aggressive pediatric CNs. Our institutional experience supports the conservative management of CN, including withholding RT until signs of recurrence regardless of resection extent or Ki-67.