The Effects of Surgery and Adjuvant Therapy on Survival Outcomes in Clear Cell Ependymomas: A Systematic Review and Meta-Analysis of Individual Patient Data

The survival outcomes of clear cell ependymomas are poorly understood. This study clarifies the role of surgery and adjuvant therapy when this morphologically distinct tumor is encountered.A systematic search for studies relating to clear cell ependymomas was conducted. Primary outcomes were progression-free survival and overall survival. Prognostic variables were age, sex, tumor consistency, extent of resection, and postoperative adjuvant therapy. Kaplan-Meier survival curves were generated and compared by the log-rank test. Multivariate Cox regression models were constructed, interrogated with Schoenfeld residuals, and used to identify independent prognostic factors.Of the 384 articles retrieved, 8 articles comprising 77 cases of clear cell ependymoma were included. Five-year overall survival and progression-free survival were 58.1% (95% confidence interval [CI], 46.3%-72.9%) and 46.3% (95% CI, 34.2%-62.8%), respectively. Kaplan-Meier analysis with the log-rank test showed that gross total resection was superior to subtotal resection in prolonging survival (P = 0.047) and delayed time to recurrence (P0.01). Multivariate analysis confirmed gross total resection as an independent protective factor against relapse (odds ratio, 0.39; 95% CI, 0.17-0.89; P = 0.03). Age50 years predicted longer overall survival (odds ratio, 0.16; 95% CI, 0.05-0.49; P0.01). Postoperative adjuvant therapy after gross total resection did not affect overall survival (P = 0.98) or progression-free survival (P = 0.93). Adjuvant therapy after subtotal resection favored improved overall survival (P = 0.052).Clear cell ependymomas are particularly aggressive in those aged50 years. Gross total resection remains the cornerstone of management. Postoperative adjuvant therapy is likely to be of survival benefit only after subtotal resection.