Background: This study investigated the relevance of prognostic factors and the impact of histological features in posterior fossa ependymoma.
Methods: The charts of 26 patients (aged 1-59 years, mean 20.6 years; 11 adults) with posterior fossa ependymoma operated on between January 1983 and December 1994 were reviewed and patients followed up (mean: 93 months).
Results: Gross total resection was performed in 18 patients (69%), subtotal in seven patients (27%), biopsy in one patient (4%). One patient (3.8%) developed respiratory complications and died. All patients underwent posterior fossa radiotherapy (5000 cGy) after surgery. Four children first received chemotherapy and then radiotherapy only when at least 3 years old. Eleven patients (42%) received radiotherapy and subsequently chemotherapy. The 5-year survival rate was 90% for adults and 40% for children (</= 6 years).
Conclusions: This review suggests that a) younger patients (</= 6 years), despite multimodality treatment, have a poor prognosis; b) the microanatomical location of the tumor (lateral recess, roof, and floor) influences the extent of tumor removal (p < 0.05); c) longer survivals are associated with complete removal (p < 0.05); d) the histological feature most often related to a poor prognosis is a high mitotic index (p < 0.05), whereas vascular proliferation (p = 0.149), necrosis (p = 0.215), nuclear atypia (p = 0.384) and high cellularity (p = 0.786) do not affect survival; e) histological classification (WHO) does not reflect different survival rates between ependymomas and anaplastic ependymomas (p = 0.082).