Evaluating the Efficacy and Survival Outcomes of Radiation Therapy in High Grade Ependymoma: Insights from the National Cancer Data Base

Introduction: High-grade ependymoma is an aggressive central nervous system malignancy. In patients receiving surgical interventions, adjuvant radiation is often followed to manage residual tumors or to prevent recurrence; however, the clinical effects remain controversial. This study aims to assess the clinical effects of different treatments, compare radiation modalities, and identify potential risk factors.

Methods: Patients with high-grade ependymoma were identified from the National Cancer Data Base from 2004 to 2017 and were categorized into two groups: radiation and no-radiation. Univariate analyses were performed to compare demographic, treatment and outcome data. Kaplan-Meier (KM) survival analysis was used to assess the overall survival (OS). Cox proportional hazards model and logistic regression model was used to identify potential risk factors.

Results: Out of 420 high-grade ependymoma patients identified, 160 received adjuvant radiation therapy while 260 did not. While both groups were similar in age, racial, residential and financial distributions; female patients were found more prevalent in radiation group (55.6% vs 44.2%), while male patients were more prevent in the no-radiation group (55.8% vs 44.4%) (p=0.023). Patients receiving adjuvant radiation were more likely to receive chemotherapy than the no-radiation group (40.6% vs 8.5%, p< 0.001). Photon was the mainstay agent used (61.2%). The 5-year mortality rate was significantly higher in the radiation group (50.0% vs 18.6%, p< 0.001). KM survival analysis revealed that while STR alone was associated with the best OS, followed by GTR alone; radiation combined with GTR was associated with the worst OS (p < 0.0001). Moreover, patients receiving conformal radiation therapy (CRT) had significantly better OS than ones receiving Intensity-modulated therapy (IMT) or photons (p < 0.0001). Multivariate analysis identified chemotherapy as a risk factor associated with a remarkably increased risk of mortality (HR:7.59, p< 0.001), while CRT was found to be associated with a reduced risk (HR:0.03, p< 0.001).

Conclusion : Adjuvant radiation therapy in general was associated with worsened survival in patients with high-grade ependymoma, while among different modalities, IMT was more favorable in improving survival. These findings emphasize the need for multidisciplinary consideration in the application of radiation therapy.