Development and Validation of a Predictive Nomogram for Patients With Myxopapillary Ependymoma: A Surveillance, Epidemiology, and End Results (SEER) Retrospective Cohort Analysis.

Study Design: Retrospective Study.

Objective: Myxopapillary ependymomas (MPEs) are a unique subgroup of spinal ependymomas originating from the filum terminale's ependymal glia. The 2021 WHO classification reclassified all MPEs as grade 2, recognizing their higher recurrence risk. Due to their rarity, our objective with this study is to understand MPEs' clinical course and optimal management through a large retrospective cohort analysis.

Methods: From the years 2000 to 2020, patients with MPEs were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariable Cox proportional hazard models were run to identify variables that had a significant impact on the primary endpoint of overall survival (OS). A predictive nomogram was built to predict 5-year and 10-year survival probability.

Results: This retrospective cohort includes 1373 patients. Patients 65 years or older at diagnosis had a poorer OS ( < 0.001). Most patients received subtotal resection. Only 320 patients (23%) received gross total resection (GTR). Patients that received GTR had the best OS when compared against all other modalities of treatment ( < 0.05). Receiving radiotherapy did not affect OS in patients with MPE ( = 0.2). Nomogram includes patient age and treatment modalities, demonstrating acceptable accuracy in estimating the survival probability at 5-year and 10-year intervals, with a C-index of 0.80 (95% CI of 0.71 to 0.90).

Conclusion: This study highlights the survival benefit of GTR in the treatment of patients with MPE. The role of adjuvant radiotherapy remains unclear as it did not seem to improve OS. The nomogram stratifies the risk of survival in patients with MPE based on age and treatment modality.