paediatrics Brussels 17

ependymomas, although a few have also included pa-

tients with MPEs [14–18]. According to these reports,

the mainstay of spinal ependymoma treatment is sur-

gery to obtain a histologic diagnosis and resect as much

of the tumor as possible. Postoperative radiotherapy

(RT) has also been advocated as an additional mean of

controlling spinal ependymomas in patients who un-

dergo subtotal resection (STR) [14–18]. However, the

respective roles of surgery and adjuvant RT in the

treatment of spinal ependymomas require further

study. For ependymomas, some investigators have

advocated minimal surgery and adjuvant RT, whereas

others have reported good clinical outcomes with gross

total resection (GTR) alone [19–23]. These viewpoints

are not necessarily relevant to the management of

MPE, however, which represents a more favorable,

histopathologic variant of ependymoma with a distinct

clinical course.

In this paper, we report the outcomes from a single

institutional experience with 35 spinal MPEs treated

with either surgery alone or surgery and adjuvant RT.

Patients and methods

Study group

This study involved 35 patients with histologically

verified spinal MPE treated at The University of Texas

M.D. Anderson Cancer Center between 1968 and 2002.

The institutional review board at M.D. Anderson

Cancer Center approved the study design, which in-

volved a retrospective review of the patients’ medical

records and a waiver of informed consent. The infor-

mation necessary for the study was obtained through

this review. The current vital status of all 35 patients

was obtained from the M.D. Anderson Cancer Center

tumor registry, the United States Social Security

database, mailed questionnaires, and telephone inter-

views. Follow-up data of varying duration were avail-

able for all patients in this study.

Surgical treatment

The extent of surgery was determined from the surgical

reports and/or postoperative imaging studies. The

surgery was classified as a GTR if the surgeon had

described a complete removal of the tumor or if there

was no evidence of tumor on scans from postoperative

computed tomography (CT) or magnetic resonance

imaging (MRI). The surgery was classified as a STR if

the surgeon had observed unresected tumor in the

operative bed or if a tumor was visible on follow-up

imaging studies.

Radiation treatment

All patients were treated with either linear accelerators

that used 6 MV or 18 MV energies or a

Co machine

(for patients treated during the earlier part of the

study). The most common technique used was a single

posterior–anterior field (in 86% of the patients);

although 14% of the patients received RT with

3-dimensional treatment planning. The RT treatment

volume was the primary tumor plus a 3–5 cm margin

based on the imaging results and the treating physi-

cian’s preferences. The cone-down field encompassed

the primary tumor with a 2 cm margin.

Chemotherapy

No patient in this study received initial or adjuvant

chemotherapy.

Four patients received salvage

chemotherapy due to recurrence of leptomeningeal

disease.

Functional evaluation

Neurologic function was evaluated by use of a Frankel

classification system (A = Complete motor and sen-

sory loss, B = Preserved sensation only, C = Motor

and sensory incomplete function, D = Useful motor

function, E = No motor or sensory function disorder)

[24]. Grades were assigned before adjuvant RT and last

follow-up visits.

Statistical analysis

Data analysis was performed by using Stata 9.0 statis-

tical software (Stata, College Station, TX). The Pear-

son’s

test was used to assess measures of association

in frequency tables. The survival function was deter-

mined by using Kaplan–Meier estimates. The log-rank

test was used to assess the equality of the survival

function across groups. The equality of means for

continuous variables was assessed by using the

-test.

Statistical tests were based on a two-sided significance

level, and a

value of 0.05 or less was considered to be

statistically significant.

The survival time was calculated from the diagnosis

date to the first occurrence of the considered event

(i.e., local spine recurrence alone, distant spinal failure

alone, or any recurrence). More specifically, overall

survival (OS) was the time from diagnosis to death

J Neurooncol (2006)

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