paediatrics Brussels 17

Pediatr Blood Cancer 2004;42:457–460

PART OF PROCEEDINGS Review of Radiotherapy Dose and Volume for Intracranial Ependymoma {

Roger E. Taylor, MA , FRCP , FRCR *

Background. Radiotherapy (RT) is well established in the management of intracranial ependymoma (EP) and post-operative RT is employed for the majority of patients. There are no randomised trials of RT in EP and evidence for dose and volume relies on retro- spective single institution series, usually com- prising a heterogeneous mix of relatively small numbers of patients recruited over several decades. Procedure. The literature including RT dose and response data reported since the early 1990s was reviewed. Results. Five-year overall survival (OS) ranges from 40 to 79%. There is some evidence of a dose response relationship from < 45 Gy to > 50 Gy. In the majority of series outcome is related to WHO grade and extent of resection. There is no evidence of benefit for ‘prophylactic’ craniosp-

inal RT (CSRT). In all series there is a significant risk of local recurrence, usually within the target volume. Early results of conformal RT have suggested that a margin for CTV of 1 cm around the post-operative tumour bed and any residual GTV is feasible. Conclusions. The main aims of future studies will be to maximise the number of patients achieving complete resection, and RT dose escalation. Hyperfractionated radiotherapy (HFRT) has been employed in some studies and results are awaited. The role of CSRT needs to be evaluated further for patients presenting with leptomeningeal metastases. Multi-institutional and international studies are necessary to improve understanding of the clinical beha- viour, biology and management of EP. Pediatr Blood Cancer 2004;42:457–460. 2003 Wiley-Liss, Inc.

Key words: dose-response; ependymoma; prognosis; radiotherapy; volume

terminale region of the spinal cord and are the most common spinal cord tumour in this location. For many years radiotherapy (RT) has been established as an important modality in the treatment of intracranial EP. The evidence for the benefit of post-operative RT compared with surgery alone is based on a number of retrospective series [2,3]. The benefit for post-operative RT compared with surgery alone has also been demon- strated in several more recent series, 45% versus 0% 5- year event-free survival (EFS) [4] and 51–70% versus 13% 5-year progression-free survival (PFS) [5]. This study reports a review of the more recent literature since the early 1990s which includes data on dose and volume for RT for EP. Interpretation of the literature is confounded by the lack of randomised studies, with the literature consisting mainly of single institution retrospective comparisons of different dose/fractionation regimens. In these series, patients have been accrued usually over several decades. Most series are small, comprising a

INTRODUCTION Ependymomas are relatively uncommon, accounting for 5–10% of brain tumours in the paediatric age group. They arise from the ependymal lining of the ventricular system. They can occur at any site within the ventricular system or in the spinal canal. Approximately two-thirds are infra- tentorial, usually arising in the ependymal lining of the 4th ventricle. Patients with tumours arising in the posterior fossa generally present with signs and symptoms of raised intracranial pressure. Extension of a ‘tongue’ of tumour through the foramen magnum and into the upper cervical region occurs in approximately 50% of patients with posterior fossa tumours. Patients with supratentorial tu- mours generally present with focal neurological symptoms and signs. Spread of EP is primarily local. Although gadolinium-enhanced MRI of the craniospinal axis and CSF cytology are essential components of the work-up for these patients, the risk of leptomeningeal seeding at diagnosis is low, generally of the order of 5–10%. The following histological subtypes of EP [1] are seen:

—————— Cookridge Hospital, Leeds, United Kingdom

myxopapillary ependymoma (WHO Grade I), ependymoma (WHO Grade II), anaplastic ependymoma (WHO Grade III).

{ This manuscript was originally submitted to and accepted for publication in Medical & Pediatric Oncology by its Editor-in-Chief, Dr. G. D’Angio. *Correspondence to: Roger E. Taylor, Cookridge Hospital, Leeds

LS16 6QB, UK. E-mail: Roger.Taylor@Leedsth.nhs.uk Received 28 May 2003; Accepted 28 August 2003

Myxopapillary EP are slowly growing lesions that are almost exclusively located in the conus and filum

2003 Wiley-Liss, Inc. DOI 10.1002/pbc.10470