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resection (GTR) in 26, near-total resection (NTR;
#
5 mm
thickness residual) in 6, and subtotal resection (STR) in 5 pa-
tients. Seventeen patients had anaplastic tumor grade, 6 were
found to have focal anaplasia, and the remainder had differ-
entiated EP.
RT
1
: initial irradiation
A variety of dose, volume, and fractionated regimens were
used for the initial treatment. Thirty-six patients were treated
by using conventional fractionation (1.6–2.0 Gy/d) to 60.4
(
n
= 1), 59.4 (
n
= 22), 55.8 (
n
= 2), 54 (
n
= 5), 50.4 (
n
=
2), 50 (
n
= 1), 48 (
n
= 1), 40 (
n
= 1), and 37.8 Gy (
n
= 1).
Two patients were treated by using hyperfractionated irradi-
ation (1.2 Gy/d) to 69.6 Gy. Three patients were treated with
supplemental radiosurgery as part of their initial manage-
ment: 1 with 8 Gy after fractionated 40 Gy, 1 with 9 Gy after
fractionated 54 Gy, and 1 with 15 Gy after fractionated 59.4
Gy. One patient received CSI to 30.4 Gy followed by focal
fractionated irradiation to 48 Gy as a part of initial manage-
ment. All patients were treated with 4- or 6-MV photons.
Failure after RT
1
and treatment before RT
2
Median time to failure after RT
1
was 19 months (range,
3–73 months). Local failure (
n
= 21) occurred with a median
time of 20 months (range, 9–73 months), metastatic failure
(
n
= 13) occurred with a median time of 22 months (range,
3–62 months), and combined local and metastatic failure
(
n
= 4) occurred with a median time of 10 months (range,
7–26 months;
Fig. 3 ). At the time of RT
1
relapse, 2 patients
were treated briefly with chemotherapy (ifosfamide, carbo-
platin, and etoposide for two cycles) and 35 of 38 patients
were treated with additional surgery. All 4 patients with com-
bined local and metastatic failure underwent attempted resec-
tion of local and metastatic disease (one to four metastatic
sites/patient), and GTR was achieved in 2 patients. Twelve
of 13 patients with metastatic failure underwent metastasec-
tomy (one to three metastatic sites/patient). The extent of re-
section was characterized as GTR in 7, NTR in 3, and STR
in 2 patients. Nineteen of 21 patients with local failure un-
derwent GTR (
n
= 12), NTR (
n
= 4), or STR (
n
= 3).
RT
2
: radiosurgery
Six lesions in 6 patients were treated by means of radiosur-
gery using a median dose of 18 Gy (range, 15–20 Gy). Le-
sions in 5 patients were entirely within the high-dose
volume of previous treatment; the lesion in the sixth patient
was an isolated metastasis to the lateral ventricle. Median
time from initiation of RT
1
to RT
2
was 21.9 months (range,
7.5–67.7 months), and from RT
1
failure to RT
2
, 1.4 months
(range, 0.4–2.3 months). Four patients underwent surgery be-
fore RT
2
, resulting in GTR (
n
= 2) or STR (
n
= 2). Two pa-
tients experienced progression with local failure at 6.3 and
Fig. 2. Example of craniospinal and metastatic site dosimetry (second course of radiotherapy [RT
2
]) for ependymoma
after prior focal radiation therapy (RT
1
). The central isodose on the RT
1
plan (white) represents the prescription dose of
59.4 Gy.
Ependymoma reirradiation
d
T. E. M
ERCHANT
et al
.
89