Multidisciplinary management of pediatric intracranial ependymoma

Abstract

Pediatric intracranial ependymoma is a rare disease representing approximately 7% of brain tumors in children aged 15 years or younger. Due to the relative rarity of these tumors, a clear standard therapy has been difficult to establish. The mainstay of treatment is surgical resection and the majority of data demonstrate improved outcome with gross total resection. The standard of care also includes postoperative radiation therapy for most patients with grade II and III tumors. Chemotherapy has been used in many capacities in this disease; however, its optimal role is yet to be defined. Current controversies such as treatment with surgery alone in completely resected tumors, use of chemotherapy for subtotally resected tumors and use of adjuvant postradiation chemotherapy are incorporated into the design of the current Children's Oncology Group clinical trial.

Figure 1.. Histological features of an ependymoma.

(A) Perivascular pseudorosettes and (B) true ependymal rosettes. Images courtesy of Arie Perry, University of California San Francisco, CA, USA.

Figure 2.. Radiographic appearance of an ependymoma.

(A) Fourth ventricular mass with extensive tumor extension through the foramen magnum. (B) Supratentorial tumors are more likely to have a cystic component.

Figure 3.. Pre- and post-operative MRI of an ependymoma patient.

(A) Preoperative MRI of an ependymoma. (B) Immediate postoperative images demonstrate gross total resection. (C) Imaging at 3 weeks, however, demonstrates how the resection bed will briskly enhance.

Figure 4.. Treatment volumes for radiation therapy following gross total resection for grade II or III ependymoma.

Yellow: resection cavity; red: clinical target volume is a 1-cm expansion; and blue: planning target volume is an additional 0.5-cm expansion.

Figure 5.. Dosimetric comparison of a five-beam intensity-modulated radiation therapy plan and a single-proton beam plan.

(A) A five-beam intensity-modulated radiation therapy plan and (B) a single proton beam plan. Note the similar conformality of the high-dose region, but there is much less low dose to the uninvolved brain with the proton plan. Images courtesy of Beth Pierburg, Barnes-Jewish Hospital, St Louis, MO, USA.