Ependymomas: development of immunotherapeutic strategies

Ependymomas are among the most challenging childhood brain tumors. Although 50-70% of ependymomas are cured with surgery and irradiation, a significant percentage of tumors recur. Ependymomas that are not amenable to complete resection at diagnosis have a particularly poor prognosis, and the vast majority of affected children experience tumor recurrence. Although transient responses have been observed in recurrent tumors treated with re-irradiation and several chemotherapy regimens, long-term disease control is rarely achieved. Children with recurrent disease commonly experience cumulative neurological morbidity from repeated surgical and adjuvant therapy interventions and almost universally succumb to refractory tumor progression. Accordingly, conceptually new treatment approaches are needed, both to decrease the risk of tumor recurrence and to enhance disease control in those children who experience recurrent disease. This article reviews the current application of risk-based treatment stratification at diagnosis, the rationale for exploring the role of novel therapeutic strategies such as immunotherapy at recurrence and the concept behind a vaccine-based trial for these tumors.