Current Management of Childhood Ependymoma

Radiation therapy has long been a mainstay in the treatment of ependymoma. Concerns about the long-term effects of radiation therapy have made many parents and caregivers wary of this treatment modality. However, with the advent of conformal radiation and evidence supporting its use in younger children (ie, < 3 years old), the standard of care for childhood ependymoma is rapidly evolving to include immediate postoperative radiation therapy for all pediatric patients. The role of chemotherapy in the treatment of ependymoma has diminished recently because (1) chemotherapy fails to delay radiation therapy for a meaningful period of time; (2) tumors that progress during chemotherapy do not respond as well to subsequent irradiation; and (3) the combination of chemotherapy and irradiation does not improve overall survival. However, chemotherapy may make residual tumor more amenable to a second resection. Fewer than 50% of pediatric patients with ependymoma undergo complete resection before receiving radiation therapy. Because the extent of resection is one of the most important prognostic factors in the treatment of this disease, increasing the rate of complete resections is a significant means of increasing long-term survival. By incorporating current concepts of ependymoma, a more uniform approach to the treatment of this disease can be developed. In addition, by combining the best available means of detecting and managing side effects, the future for pediatric patients with ependymoma remains optimistic. This review presents historical and current practices used to treat ependymoma, and is intended to provide an information framework for caregivers so that they can assist parents in the decision-making process. [ONCOLOGY 16:629-648, 2002]

Ependymoma accounts for 8% to 10% of all childhood central nervous system (CNS) tumors, with fewer than 170 new cases diagnosed annually in the United States in children and adults younger than 25 years old.[1] The mean age at the time of diagnosis ranges from 51 to 71 months,[2-5] and 25% to 40% of those diagnosed are younger than age 3.[6] Survival statistics for ependymoma are generally disappointing: The historical 5-year survival estimate is 50% to 64%, and the historical progression-free survival estimate is 23% to 45%.[2,4,7-9] Recurrences are typically local, and the median time to recurrence is 13 to 25 months.[2-4,7,9,10] Approximately 20% of failures involve distant recurrence, and late recurrences are not uncommon.

Ependymoma develops from the neuroepithelial lining of the ventricles of the brain and the central canal of the spinal cord; 90% of tumors are located intracranially, with 30% occurring above the tentorium and 60% below it (Figure 1).[1] Supratentorial ependymoma arises either from the lateral or third ventricle (60%) or from the cerebral hemisphere (40%).[1,11] Infratentorial ependymoma arises from one of three specific sites within the fourth ventricle: the floor (60%), the lateral aspect (30%), or the roof (10%).[12,13] Tumors that arise from the floor of the fourth ventricle may extend through the foramen of Magendie and over the dorsal surface of the spinal cord. Those that arise from the lateral aspect of the fourth ventricle can extend out of the foramen of Luschka and into the cerebellopontine angle and along the anterior aspect of the pons and medulla (Figure 2).

Complete surgical removal of posterior fossa ependymoma arising from the floor or lateral aspect of the fourth ventricle is difficult because these tumors are typically close to the surface of the brainstem and cranial nerves. Fortunately, neuraxis dissemination at the time of diagnosis is rare and occurs in fewer than 7% of patients (Figure 3).[3]

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