Radiotherapy in addition to surgical resection may not improve overall survival in WHO grade II spinal ependymomas

Objectives: Spinal ependymomas are rare intramedullary neoplasms. The paucity of cases limits the ability to conduct large prospective studies. Current guidelines recommend maximal safe resection followed by adjuvant radiotherapy (RT) in cases of grade II spinal ependymomas with subtotal resections (STR) and all grade III spinal ependymomas. Herein we assess the impact of RT on survival in grades II and III spinal ependymomas.

Patients and methods: The National Cancer Database was queried for adult patients with WHO grades II or III spinal ependymomas diagnosed between 2004 and 2014 who underwent resection or biopsy. Kaplan-Meier and multivariable Cox regression models were used to determine the impact of radiotherapy on survival.

Results: A total of 1058 patients met inclusion criteria. Most patients (85.9 %) received a biopsy/STR versus gross total resection (GTR, 14.1 %). Radiotherapy was preferentially performed in those with residual tumor (p = 0.001). We found a 10-fold increased hazard of death in grade III versus grade II tumors (HR: 10.33; 95 % CI: 5.01-21.3; p < 0.001). Age positively correlated with worsened survival (HR: 1.04; 95 % CI: 1.02-1.10; p < 0.001). Adjuvant RT did not reduce the hazard of death for the cohort overall (HR: 1.08; 95 % CI: 0.55-2.10; p = 0.810) or among those with grade II tumors (HR: 0.90; 95 % CI: 0.38-2.10; p = 0.810). We found no additional survival benefit of GTR compared to biopsy/STR (HR: 0.52; 95 % CI: 0.19-1.50; p = 0.217).

Conclusion: While RT may improve progression-free survival, it may not impact overall survival in surgically resected grade II and III spinal ependymomas. Future studies should evaluate the impact of RT on local recurrence and symptomatic improvement.