Influence of tumor grade and CD95 expression on progression-free survival following surgery and irradiation for localized intracranial ependymoma

ABSTRACT

This study was conducted to evaluate the impact of extent of tumor resection, histological grade and CD95 expression on the progression-free survival [PFS] after surgical excision and irradiation [RT] for patients with localized intracranial ependymomas. This study includes thirty four patients with localized intracranial ependymomas with median age of 23.5 [range 2-65] at the time of surgical excision. All patients underwent microsurgical resection followed by RT with or without chemotherapy during the period between January 2000 and June 2003. Ten patients were histologically identified as anaplastic ependymoma [AEP]. Immunohistochemical staining for CD95 was applied as a marker for apoptosis for all specimens of the studied group. The extent of surgical resection was estimated as gross total resection in 21 patients [61.8%], near total resection in 4 patients [11.8%] and subtotal resection in 9 patients [26.5%]. The median dose of RT to the primary site was 55Gy. Only 8 patients received pre RT chemotherapy [CTh]. At a median follow up period of 24.5 months [range 6-51 months], 25 patients were alive, while, at a median follow up of 22 months [range 8-49 months], progression occurred in 15 patients [12 local and 3 local and distant], with a median time to failure after RT of 18 months [range 5-37 months]. There was a significant influence of gross total resection [p=0.003] and tumor grade [p=0.009] on the PFS after RT. The two years PFS rate was 26% +/- 13% for patients with AEP compared with 82% +/- 7% for patients with EP. When correlating these findings with the extent of surgical resection, age less than 4 years, pre-RT CTh and CD95 expression, they remained significant. AEP was more frequent in the supratentorial ependymomas. Five of 9 patients with supratentorial tumors developed recurrence and all were anaplastic type [AEP] and CD95-stained tumors. Progression-free survival was found to be significantly influenced by the extent of surgical resection. Tumor grade and apoptosis have an impact upon the outcome of patients with ependymoma treated with surgery and RT. CTh before RT had a worse effect on the PFS and overall survival.