Myxopapillary ependymoma: a SEER analysis of epidemiology and outcomes

Myxopapillary ependymoma (MPE) is an exceedingly rare tumor histology. While surgery is clearly the treatment of choice, controversy exists regarding the role of adjuvant radiotherapy (RT). Using the Surveillence, epidemiology, and end results (SEER) database, we aimed to determine the epidemiology, prognostic factors, and treatment-related outcomes for MPE. A total of 773 cases were found in the SEER database. The incidence in the American population was found to be 1.00 per million person-years. On multivariate analysis, receipt of surgery (HR = 0.14, CI = 0.06-0.35, p < 0.001), receipt of RT (HR = 4.06, CI = 1.87-8.81, p < 0.001), age less than 30 (HR = 0.24, CI = 0.08-0.72, p = 0.01), and Caucasian race (HR = 0.37, CI = 0.13-0.996, p = 0.049) were statistically significant prognostic factors. The mean tumor size among those receiving RT (4.6 cm) was significantly larger than among those not receiving RT (3.2 cm, p = 0.0002). Those who lived in metropolitan areas were more likely to receive RT than those who did not. Given multiple previous studies show that RT improves PFS and the discrepancy in tumor size, selection bias is likely a significant contributor to the apparent negative impact of RT on OS. Regardless, surgery remains the most crucial aspect in the care of patients with MPE.