1569 / 1708
amenable to complete resection in up to 94% of cases
[19, 30, 31]. In our study, GTR was possible in a
somewhat smaller percentage of patients with MPE, in
keeping with the more irregular shape of MPEs and
their contact with multiple nerve roots. However, in
MPE patients in our study undergoing GTR, the data
suggest that GTR alone may not be sufficient, and that
adjuvant RT should be given and is indicated even in
the setting of GTR. This is in contrast to spinal epen-
dymoma in which GTR without RT may be deemed
sufficient treatment.
In this study, 12 patients (34%) experienced disease
recurrence, 8 at the local site alone (10-year LC rate
was 72%). A similar pattern of failure has been noted
in other retrospective series. Whitaker et al. [16]
showed that in 43 patients treated with postoperative
radiation, 6 of 8 with recurrent tumors had failures at
the primary site. Similarly, of the 22 patients who
underwent surgery and postoperative RT in the study
by Shaw et al. [25], 6 of 7 failures were at the primary
site.
We did not observe any extraneural metastases in
our study but did observe four recurrent tumors that
were distant from the site of the primary tumor. Two
patients had recurrences in the brain. Although rare,
this pattern of failure has been noted in other series.
Whitaker et al. [16] found a 5.8% incidence of cranial
relapse in 259 patients with spinal ependymomas; the
pattern of failure in our series support the use of local
field irradiation for localized spinal MPE, regardless of
the extent of the resection.
In our current study, the addition of postoperative
RT to surgery was associated with significantly better
10-year PFS rates (75% for surgery + RT vs. 37% for
surgery alone,
P
= 0.04) and 10-year LC rates (86% for
surgery + RT versus 46% for surgery alone,
P
= 0.03).
Several authors have similarly reported improved
survival rates and decreased recurrences in patients
treated with postoperative RT after STR or GTR in
various series of spinal ependymoma or MPE [8, 13, 15,
17, 26, 30, 32].
The optimal dose of radiation for spinal ependy-
momas has been debated in the literature. This has
been extrapolated to MPE, which is usually located
in the cauda equina. Most authors recommend doses
of 40–50 Gy [16, 26, 27, 29]. In a study by Garcia
et al. [33], a dose–response effect was seen. Patients
who received doses greater than 40 Gy had signifi-
cantly improved PFS rates. Similarly, Marks and
Adler [32] recommended a dose of 40-Gy for totally
resected MPEs. In our study, which analyzed the
effect of total radiation dose using 45 Gy as the
cutoff dose; we did not find any significant differ-
ences between the two dose groups, most likely
because most patients received 50 Gy to the tumor
site, and only four patients received doses equal to
or less than 45 Gy.
In conclusion, the long-term survival for spinal MPE
managed with surgery and adjuvant radiotherapy is
favorable. Failures occur exclusively in the neural axis,
mainly in the primary site. Regardless of the extent of
surgery, adjuvant RT to the primary disease site
appears to significantly reduce the rate of tumor
progression.
References
1. Damjanov I, Linder J (eds) (1996) Anderson’s pathology,
10th edn. S Mosby, St. Louis, pp 2753–2755
2. Peschel RE, Kapp DS, Cardinale F, Manuelidis EE (1983)
Ependymomas of the spinal cord. Int J Radiat Oncol Biol
Phys 9:1093–1096
3. Shuman RM, Alvord EC, Leech RW (1975) The biology of
childhood ependymomas. Arch Neurol 32:731–739
Table 3
Treatment characteristics and incidence of recurrence in selected spinal MPE series
Reference
Number
of cases
Time
period
Mean age
(years)
E/MPE
a
GTR/STR-Bx Adjuvant
RT (%)
Mean
follow-up
(month)
Relapse
rate (%)
OS rate
at 10 years
(%)
Sonneland et al. [9] 77
1924–1985 36.7
0/77
45/32
46
N/A 17
N/A
Shaw et al. [25]
22
1963–1983 47
12/10
8/14
100
156
31.8
95
Whitaker et al. [16] 58
1950–1987 40
34/24
14/44
74
70
22.4
100
Waldron et al. [18] 59
1958–1987 37
43/16
16/43
100
130
18.7
75
Wen et al. [27]
20
1960–1984 36
20/9
7/13
65
N/A 30
86
Schild et al. [14]
35
1963–1994 33.5
23/12
10/25
100
124.8
N/A 100
b
Clover et al. [26]
11
1971–1990 36
11/6
1/10
73
88
50
c
80
Present study
35
1968–2002 33
0/35
21/14
63
127
34
97
a
E/MPE = Ependymoma/myxopapillary ependymoma; GTR = Gross total resection; STR = Subtotal resection; Bx = Biopsy;
RT = Radiotherapy; OS = Overall survival; N/A = Not available
b
5-year OS rate for MPE subgroup
c
Relapse rate for MPE subgroup
J Neurooncol (2006)
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