Clinical course and progression-free survival of adult intracranial and spinal ependymoma patients.

BACKGROUND: Ependymomas are rare CNS tumors. Previous studies describing the clinical course of ependymoma patients were restricted to small sample sizes, often with patients at a specific institution. METHODS: Clinically annotated ependymoma tissue samples from 19 institutions were centrally reviewed. Patients were all adults aged 18 years or older at the time of diagnosis. Potential prognostic clinical factors identified on univariate analysis were included in a multivariate Cox proportional hazards model with backwards selection to model progression-free survival. RESULTS: The 282 adult ependymoma patients were equally male and female with a mean age of 43 years (range, 18-80y) at diagnosis. The majority were grade II (78%) with the tumor grade for 20 cases being reclassified on central review (half to higher grade). Tumor locations were spine (46%), infratentorial (35%), and supratentorial (19%). Tumor recurrence occurred in 26% (n = 74) of patients with a median time to progression of 14 years. A multivariate Cox proportional hazards model identified supratentorial location (P < .01), grade III (anaplastic; P < .01), and subtotal resection, followed or not by radiation (P < .01), as significantly increasing risk of early progression. CONCLUSIONS: We report findings from an ongoing, multicenter collaboration from a collection of clinically annotated adult ependymoma tumor samples demonstrating distinct predictors of progression-free survival. This unique resource provides the opportunity to better define the clinical course of ependymoma for clinical and translational studies.

Histological predictors of outcome in ependymoma are dependent on anatomic site within the central nervous system.

Ependymomas originate in posterior fossa (PF), supratentorial (ST) or spinal cord (SC) compartments. At present, grading schemes are applied independent of anatomic site. We performed detailed histological examination on 238 World Health Organization grade II and III ependymomas. Among PF ependymomas, the presence of hypercellular areas, necrosis, microvascular proliferation and elevated mitotic rate (all P < 0.01) were significantly associated with worse progression-free survival (PFS), while extensive ependymal canal formation was not (P = 0.89). Similar to the PF tumors, microvascular proliferation (P = 0.01) and elevated mitotic rate (P = 0.03) were significantly associated with worse PFS in the ST tumors. However, in contrast to PF tumors, extensive ependymal canals (P = 0.03) were associated with worse clinical outcome in ST ependymomas, but hypercellularity (P = 0.57) and necrosis (P = 0.47) were not. On multivariate Cox regression, after adjusting for relevant clinical variables, individual histological factors and a composite histological score remained significant among ST and PF ependymoma. In contrast to both PF and ST ependymoma, histological features were not found to be associated with PFS in SC tumors. Taken together, the clinical relevance of specific histological features in ependymoma appears to be related to the anatomic site of origin and suggests that site-specific grading criteria be considered in future classification systems.