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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*
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:
myxopapillary ependymoma (WHO Grade I),
ependymoma (WHO Grade II),
anaplastic ependymoma (WHO Grade III).
Myxopapillary EP are slowly growing lesions that are
almost exclusively located in the conus and filum
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
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
——————
Cookridge Hospital, Leeds, United Kingdom
{ 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:
Received 28 May 2003; Accepted 28 August 2003
2003 Wiley-Liss, Inc.
DOI 10.1002/pbc.10470