Fourth ventricle ependymomas. A study of 20 cases with survival analysis.

Twenty patients with fourth ventricle ependymoma were treated surgically at our Neurosurgery Division between January 1976 and December 1990. Ependymoblastomas and mixed gliomas operated on in the same period have not been considered. A statistical analysis of our cases and a review of the largest published series show that favourable prognostic factors are: age over 16, post-operative radiotherapy to the posterior cranial fossa and a good Karnofsky performance status (KPS) after operation. The 5-year survival rate of patients under 16 was 20%, in comparison with 60% of adults (p = 0.013). Post-operative radiotherapy to the posterior cranial fossa improved the survival markedly (5-year survival rate 68%, versus 18% without treatment; p = 0.011). The differences of survival are also significant according to a multivariate analysis (p = 0.038). Patients with a post-operative KPS over 70 had a 5-year survival rate of 61% as against 17% of the group with a worse clinical condition (p = 0.032); the multivariate analysis confirmed also that this difference was significant (p = 0.046). Pre-operative symptoms and signs, and KPS, histological grade and extent of surgical removal seem to influence the prognosis, even if the differences of survival are not statistically significant. The statistical relevance of postoperative residual tumour on CT or MRI was brought out on multivariate analysis (p = 0.044).