High failure rate in spinal ependymomas with long-term follow-up

Abstract

Data on spinal ependymomas are sparse, and prognostic factors remain controversial. The primary aim of this study is to review a historical cohort, with large patient numbers and long follow-up, and provide estimates of time to progression (TTP) and survival after progression. As a secondary aim, we assess the effects of potential prognostic variables. Thirty-seven patients with spinal cord ependymomas received postoperative radiation therapy from 1955 to 2001. The influences of radiation dose, extent of resection, Karnofsky performance score, tumor location, and multifocality were assessed in univariate analyses by using the Cox proportional hazards model. The median follow-up for patients who did not fail was 121 months (range, 8-312 months). Kaplan-Meier estimates of 5-, 10-, and 15-year percentage progression free are 75%+/-7.4%, 50%+/-9.1%, and 46%+/-9.3%, respectively. Median TTP, for those who recurred, is 68 months (range, 2-324 months), with 12 of 21 failures occurring after five years. Of the prognostic factors examined, only greater extent of resection significantly correlated with longer TTP (P=0.02). Local relapse rates for spinal ependymomas are higher than previously cited, with a large proportion of failures occurring more than five years after diagnosis. Extensive surgical resection correlates with longer time to recurrence, and we thus recommend maximal excision while avoiding surgical morbidity. The overall high rate of recurrence leads us to recommend radiation to doses of 45 to 54 Gy for all patients who do not have gross total resections, and long, close follow-up.