ESTRO 36 Abstract Book

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S564 ESTRO 36 2017
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Severity Index (DSI). Rosenbeks 8-points-penetration-
aspiration-scale (PAS, Rosenbek 1996) was used to
determine the severity. The Functional Oral Intake Scale
(FOIS) classified by Crary (Crary et al., 2005) was used to
assess the oral food intake of the patients.
Results
A paired t-test showed a significant change in volume of
five OARs: superior and middle pharyngeal constrictor
muscle, cricopharyngeal muscle, proximal esophagus
and transglottic larynx (p≤0.055). There was a significant
increase in volume in four OARs and a significant decrease
in the proximal esophagus. The linear regression analysis
of the volume changes of the respective OARs and the
applied dose showed no significant correlation. The binary
logistic regression showed a significantly (p=0.015) 1.5
times higher risk to suffer from dysphagia when the dose
is increased by steps of 1 Gy. No association could be
found for dose-dependent dysphonia. The results of the
FEES showed conspicuous PAS levels in all five subjects and
the FOIS scale reached grade 3 to grade 6. Also, dysphonia
ranged from a mild to a high degree. The evaluation of the
ADI-D questionnaire correlated with the degree "rather
conspicuous" in the Bauer and Rosanowski Scale. The Voice
Handicap Index showed one patient with a moderate and
four with no subjective voice disorder. Apart from
problems caused by xerostomia only minor discomfort in
respect of tumor-specific symptoms was observed based
on the EORTC QLQ-H&N35 questionnaire.
Conclusion
In this study, a tendency of increase in the volume of OARs
under RT with distinct clinical symptoms (dysphagia and
dysphonia) was detected, also after more than one
year post-RT. MRI use for RT is essential for an
optimal protection of the OARs in terms of adaptive
radiotherapy (ART) and is expected to improve treatment
as MR-guided radiotherapy (MRgRT)
.
EP-1029 Improved interobserver reproducibility in
nasopharyngeal tumor delineation using a reference
GTV
A. Lapierre1, F. Lorchel1, P. Boisselier2, B. Fleury3, F.
Craighero4, M. Deberne1, G. Gascou5, M. Rousset6, V.
Favrel1, J.B. Pialat7, J.M. Ardiet1, P. Céruse8, O. Chapet1
1 Centre Hospitalier Lyon Sud, Service de Radiothérapie,
Pierre Benite, France
2 CRLC Val d'Aurelle, Service de Radiothérapie,
Montpellier, France
3 Centre Marie Curie, Service de Radiothérapie, Valence,
France
4 Centre Hospitalier Universitaire Croix Rousse, Service
de Radiologie, Lyon, France
5 Centre Hospitalier Universitaire Saint Eloi, Service de
Radiologie, Montpellier, France
6 Centre Hospitalier Lyon Sud, Service de Radiologie,
Pierre Benite, France
7 Centre Hospitalier Universitaire Edouard Herriot,
Service de Radiologie, Lyon, France
8 Centre Hospitalier Universitaire Croix Rousse, Service
de chirurgie ORL, Lyon, France
Purpose or Objective
Standard treatment for nasopharyngeal cancer (NPC)
relies on concurrent chemoradiotherapy, using intensity
modulated radiotherapy (IMRT). Adequate tumor volume
definition is essential for precision radiotherapy such as
IMRT. However, tumor volume delineation reproducibility
on CT scans has been shown to be variable among radiation
oncologists. The main goal of this study was to assess the
reproducibility of radiologists in defining nasopharyngeal
tumor volumes, and whether a common gross tumor
volume (GTV) delineated by specialized radiologists would
improve reproducibility between radiation oncologists in
defining high risk tumor clinical target volumes (CTV) in
NPC cases.
Material and Methods
Ten patients treated at our institution over the last 5 years
for nasopharyngeal tumors were selected for the study. In
the first part of the study, five experienced radiation
oncologists were asked to independently delineate tumor
GTV and high risk tumor CTV. Meanwhile, three
radiologists independently delineated the tumor GTV on
the diagnosis MRI, after which, the radiation oncologist
were asked to delineate the high risk tumor CTV again,
using the reference GTV delineated by the radiologists.
Results
The intraclass correlation coefficient (ICC) for GTV
delineation was 0.914 for radiologists, and 0.754 for
radiation oncologists. Use of a common GTV increased the
generalized conformity index (CIgen) from 0.44 to 0.49 for
CTV delineation by the radiation oncologists.
Conclusion
Interobserver variations tend to be lower between
radiologists than radiation oncologists in the definition of
NPC tumor volumes, and that use a single reference GTV
improves reproducibility between radiation oncologists.
EP-1030 External beam radiation therapy for
locoregionally recurrent differentiated thyroid
carcinoma
C.Y. Kim1, N.K. Lee1, K.Y. Jung2, S.K. Baek2
1Korea University Anam Hospital, Radiation Oncology,
Seoul, Korea Republic of
2Korea University Anam Hospital, Otolaryngology–Head
and Neck Surgery, Seoul, Korea Republic of
Purpose or Objective
the purpose of this study was to evaluate the treatment
outcomes of external beam radiation therapy in patients
with locoregionally recurrent differentiated thyroid
carcinoma.
Material and Methods