Henry Soo-Min Park BS, Abstract Co-Author: Nothing to Disclose

Ben Frazier Taylor MD, PhD, Abstract Co-Author: Nothing to Disclose

James Byunghoon Yu MD, Abstract Co-Author: Nothing to Disclose

Michael DiLuna MD, Abstract Co-Author: Nothing to Disclose

Kenneth Berwick Roberts MD, Presenter: Nothing to Disclose

Purpose/Objective(s): Myxopapillary ependymoma (MPE) is a rare histologic variant of spinal ependymoma that is classified by the World Health Organization (WHO) as a grade I tumor, due to its benign histological features, indolent growth pattern, and long survival. However, small case series of MPE have reported relatively high rates of both local recurrence and distant central nervous system metastasis following surgical resection alone. Given the rarity of the tumor, the role of adjuvant radiation therapy (RT) for spinal MPE remains controversial. In 2004, the U.S. federal government began collecting data for “benign/borderline” central nervous system tumors and created a new International Classification of Diseases, 3rd edition (ICD-O-3) diagnosis code for MPE, which has not yet been specifically studied in a population-based analysis.Materials/Methods: Using the Surveillance, Epidemiology, and End Results (SEER) database from 2004-2007, we included all patients with histologically-diagnosed MPE (ICD-O-3 code 9394) in the spinal cord, cauda equina, or spinal meninges (ICD-O-3 codes C720, C721, and C701, respectively) who had complete surgery and RT data recorded. Bivariate and multivariate analyses were used to measure associations between demographic characteristics and likelihood of receiving surgery and/or RT.Results: A total of 286 patients were included in the analysis, among whom 32 (11%) were younger than 18 years. Median age was 41 years; 59% of patients were male and 90% were white. Gross total resection was performed in 66% of patients, partial resection in 19%, and biopsy only in 15%. RT was utilized in 17% of all patients, including 11% of patients following gross total resection, 50% of patients following partial resection, and 11% of patients following biopsy only. In multivariate analysis, there were no differences in the likelihood of receiving gross total resection or RT by age, sex, or race, but patients with partial resection were significantly more likely to undergo adjuvant RT than those with gross total resection (odds ratio 8.23, 95% confidence interval 3.97-17.06).Conclusions: On a national scale, the majority of patients with spinal MPE undergo gross total resection. Adjuvant RT is not utilized commonly following gross total resection or biopsy only, but is delivered to half of patients who underwent partial resection. Longer follow-up is needed to evaluate the potential overall and progression-free survival benefit of adjuvant RT following partial or gross total resection.

Park, H, Taylor, B, Yu, J, DiLuna, M, Roberts, K, Adjuvant Radiation Therapy in Spinal Myxopapillary Ependymoma: A Population-based Analysis.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034666.html