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Conclusion
Following de-intensified chemoradiotherapy, the rate of
patient reported xerostomia was best correlated with V15-
V55 of the combined contralateral glands at 6 months and
V15 of the combined contralateral glands and
contralateral parotid at 12 months. Dysphagia at 6 months
was best correlated with V55-V60 of the superior
pharyngeal constrictors. It was shown that all the
examined NTCP models could fit the clinical data well with
very similar accuracy. Statistically significant NTCP
thresholds could be identified for each model for the
respective organs and clinical endpoint cases.
Proffered Papers: CNS
OC-0512 MR imaging predictor of survival in pediatric
ependymoma patients after radiotherapy
F. Tensaouti
1
, A.D. Ducassou
2
, L.C. Chaltiel
3
, A.S.
Sevely
4
, S.B. Bolle
5
, X.M. Muracciole
6
, B.C.D. Coche-
Dequant
7
, C.A. Alapetite
8
, S.S. Supiot
9
, A.H. Huchet
10
,
V.B. Bernier
11
, L.C. Claude
12
, A.I.B.S. Bertozzi-Salamon
13
,
P.P. Péran
14
, P.P. Payoux
15
, A.L. Laprie
16
1
ToNIC- Toulouse NeuroImaging Center- Université de
Toulouse- Inserm- UPS-, ToNIC- Toulouse NeuroImaging
Center- Université de Toulouse- Inserm- UPS-, Toulouse,
France
2
Department of Radiation Oncology- Institut Claudius
Regaud- Institut Universitaire du Cancer de Toulouse –
Oncopole- Toulouse- France, Radiation Oncology,
Toulouse, France
3
Department of Biostatistics- Institut Claudius Regaud-
Institut Universitaire du Cancer de Toulouse-Oncopole-
Toulouse- France, Department of Biostatistics, Toulouse,
France
4
Department of Radiology- CHU Purpan- Toulouse-
France, Department of Radiology, Toulouse, France
5
Department of Radiation Oncology- Institut Gustave
Roussy- Paris- France, Department of Radiation
Oncology, Paris, France
6
Department of Radiation Oncology- CHU La Timone-
Marseille- France, Department of Radiation Oncology-,
Marseille, France
7
Department of Radiation Oncology -Centre Oscar
Lambret- Lille- France, Department of Radiation
Oncology, LILLE, France
8
Department of Radiation Oncology- Institut Curie- Paris-
France, Department of Radiation Oncology, Paris, France
9
Department of Radiation Oncology- Institut de
cancérologie de l’ouest- Nantes- France, Department of
Radiation Oncology, Nantes, France
10
Department of Radiation Oncology - CHU Bordeaux-
Bordeaux- France, Department of Radiation Oncology,
Bordeaux, France
11
Department of Radiation Oncology- Centre Alexis
Vautrin- Vandoeuvre- Nancy- France, Department of
Radiation Oncology, Nancy, France
12
Department of Radiation Oncology- Centre Léon
Bérard- Lyon- France, Department of Radiation
Oncology, Lyon, France
13
Department of pediatric- Hematology-Oncology Unit-
CHU Purpan- Toulouse- France, Department of pediatric,
Toulouse, France
14
ToNIC- Toulouse NeuroImaging Center- Université de
Toulouse- Inserm- UPS- Toulouse- France, Toulouse
NeuroImaging Center, Toulouse, France
15
Department of Nuclear Medicine- CHU Purpan-
Toulouse- France- ToNIC- Toulouse NeuroImaging Center-
Université de Toulouse- Inserm- UPS- Toulouse- France,
Department of Nuclear Medicine, Toulouse, France
16
Department of Radiation Oncology- Institut Claudius
Regaud- Institut Universitaire du Cancer de Toulouse –
Oncopole- Toulouse- France- ToNIC- Toulouse
NeuroImaging Center- Université de Toulouse- Inserm-
UPS- Toulouse- France, Department of Radiation,
Purpose or Objective
The aim of this study was to investigate the correlation
between
preoperative,
postoperative
imaging
characteristics and survival after radiotherapy in pediatric
ependymoma patients.
Material and Methods
A retrospective review of 121 patients who underwent
primary resection of ependymoma followed by radiation
therapy was undertaken utilizing quantitative volumetric
analysis
of
pre-
and
postoperative
MR
images. Preoperative tumor volume (PRTV) on Post
contrast (PC) T1 imaging , preoperative tumor volume
((PRTVF) on T2/FLAIR imaging , postoperative tumor
volume on T2/FLAIR (POTVF) and Contrast Enhancement
volume (CEPTV) ) on PC-T1 imaging were delineated by
an experienced radiation oncologist and double-checked
by a neuroradiologist, after coregistration of T2/FLAIR
imaging to the PC-T1WI. A survival analysis was done
including clinical data (Gender, tumor location, tumor
grade, the extent of resection, radiation dose) and
extracted imaging volumes. All survival times were
calculated from the date of beginning of RT. Overall
survival (OS) and disease free survival (DFS) were
estimated by the Kaplan-Meier method and using the
following first-event definitions: local and distant relapse
or death for disease free survival (DFS) and death for
overall survival (OS). Univariate analyzes were performed
using Cox proportional hazards model for quantitative
variables and the log-rank test for qualitative variables.
The hazard ratio (HR) (respectively, the survival rate at 3
years) is presented for each quantitative covariate
(qualitative respectively) with 95% confidence interval.
PRTV variable was dichotomized with the median value
(<= 43.8 cc, vs> 43.8 cc) and POTVF variable with (0 (no)
vs> 0 (presence)).
Results
At the end of analysis, 80.2 % of patients were alive, 39.7%
presented with one events (local relapse, distant relapse
or death). The median overall survival was 38.5 months
(9% IC [30.5; 47.7]). The Median age at diagnosis was 4
years (1.0-22.0), 58.7% were male, tumor location was