ESTRO 36 Abstract Book

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S668 ESTRO 36 2017
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A.L. Grosu1,14, M. Guckenberger2, T. Brunner1,14
1 University Hospital Freiburg, Radiation Oncology,
Freiburg, Germany
2 University Hospital Zürich, Department of Radiation
Oncology, Zurich, Switzerland
3 University Hospital Freiburg, Department of Visceral
Surgery, Freiburg, Germany
4 University Hospital Freiburg, Department of Nuclear
Medicine, Freiburg, Germany
5 University Hospital Halle-Wittenberg, Department of
Radiation Oncology, Halle-Wittenberg, Germany
6 University Hospital Dresden, Department of Radiation
Oncology, Dresden, Germany
7 University Klinik Rechts der Isar- TU Munich,
Department of Radiation Oncology, Munich, Germany
8 General Hospital Vienna- Medical University Vienna,
Department of Radiation Oncology, Vienna, Austria
9 University Hospital of Cologne, Department of Radiation
Oncology, Cologne, Germany
10 University Hospital Mainz, Department of Radiation
Oncology, Mainz, Germany
11 University Hospital Frankfurt, Department of Radiation
Oncology, Frankfurt, Germany
12 University Hospital Freiburg, Department of Radiology,
Freiburg, Germany
13 University Hospital Heidelberg, Department of
Radiation Oncology, Heidelberg, Germany
14 German Cancer Consortium DKTK, Partner Site
Freiburg, Freiburg, Germany
Purpose or Objective
To evaluate the inter-observer variability in the gross
tumor delineation of hepatocellular carcinoma (HCC) in a
multicenter panel.
Material and Methods
The analysis was performed within the working group on
Stereotactic Radiotherapy of the German Society for
Radiation Oncology (DEGRO). A total of 9 German,
Austrian and Swiss centers with experience in upper
abdominal stereotactic body radiotherapy (SBRT)
participated in the study. Sixteen physicians (12 radiation
oncologists, 2 liver surgeons, 1 radiologist and 1 nuclear
medicine physician) were invited to delineate the gross
tumor volume (GTV) of three anonymized HCC cases. A
multiphasic CT scan from each patient was distributed to
the panel before the annual meeting. In the first case
participants were asked to delineate a peripheral well
defined HCC. The second case included a patient with a
multifocal HCC (1 conglomerate and 1 peripheral tumor).
This patient was previously treated with transarterial
chemoembolization (TACE) and the peripheral lesion was
adjacent to the previous TACE site (lipiodol uptake site).
In the last case the participants were given a CT with an
extensive HCC involvement with a portal vein thrombosis
and inhomogeneous liver parenchyma due to extensive
cirrhosis. The inter-observer agreement (IOA) was
evaluated according to Landis and Koch.
Results
The IOA for the first case was excellent (kappa: 0.85) and
for the second case moderate (kappa 0.48) for the
peripheral tumor and substantial (kappa 0.73) for the
conglomerate. In the case of the peripheral tumor the
inconsistency is most likely explained due to the necrotic
tumor cavity after TACE caudal to the viable tumor. In the
last case the IOA was fair with a kappa of 0.34 with a
significant heterogeneity concerning the borders of the
tumor and the extent of the portal vein thrombosis (PVT).
We did not find significant differences between the
different subgroups of experts except for the last case
were the physicians who were involved in the diagnosis
(radiologists and nuclear medicine physician) showed a
better IOA (kappa: 0.64)
Conclusion
The IOA was very good among the cases were the tumor
was well defined. Yet, in complex cases were the tumor
did not show the typical characteristics or in cases with
lipiodol deposits inter-observer agreement was
compromised.
EP-1254 DVH analysis of radiotherapy of upper
gastrointestinal tumours: a model to predict toxicity.
G.C. Mattiucci1, L. De Filippo1, N. Dinapoli 1, L. Boldrini1,
S. Chiesa1, M. Bianchi1, R. Canna1, F. Cellini1, G.
Chiloiro 1, F. Deodato2, G. Macchia 2, C. Indellicati1, D.
Pasini1, A.G. Morganti3, V. Valentini1
1Università Cattolica del Sacro Cuore -Policlinico A.
Gemelli, Radiotherapy, Rome, Italy
2Fondazione di Ricerca e Cura “Giovanni Paolo II”-
Università Cattolica del Sacro Cuore, Radiotherapy Unit,
Campobasso, Italy
3Department of Experimental- Diagnostic and Specialty
Medicine – DIMES- Università di Bologna- Ospedale S.
Orsola-Malpighi, Radiation Oncology Center, Bologna,
Italy
Purpose or Objective
Tolerance of small bowel is the dose limiting factor in
radiation therapy for abdominal neoplasms. Bowel
constraints for treatment planning in abdominal
radiotherapy derive from scientific publications of pelvic
tumors. This study has the aim to evaluate dose tolerance
of small bowel and to provide a model detecting acute
toxicities in patients with upper gastrointestinal (GI)
cancer treated with radiotherapy.
Material and Methods
Patients with upper GI cancer treated between 2009 and
2016 with 3D-conformal or intensity modulated
radiotherapy (IMRT) with or without concomitant
chemotherapy were enrolled in this study. Nausea, vomit
and loss of weight, as acute upper gastrointestinal (GI)
toxicities, were scheduled using CTCAE v4.03 scale. In all
patients small bowel loops, bowel bag, liver and stomach,
if present, were contoured by a radiation oncologist on
simulation computed axial tomography according to
QUANTEC guidelines. Liver, PTVs, Small Bowel, Bowel Bag
and Stomach were selected on Dose Volume Histogram
(DVH) and their data were extrapolated. DVHs were
analyzed for this structures using R statistical software
).
Results
Data of 143 patients with a median age of 66 years (range
35-84), 79 (55,2%) resected and 64 (44,8%) unresected,
were analyzed. All patients selected had primary tumour
location cancer in upper GI tract such as pancreas (53%),
biliary ducts (15%), stomach (26%), gallbladder (3%),
gastroesophageal junction (3%). Prescribed dose ranged
between 3000 cGy and 5580 cGy with fractionaction
ranging between 180 cGy and 300 cGy. Most of patients
were treated with 3D conformal radiotherapy (92%) and
only 8% received IMRT.
Fiftytwo (36,4%) patients reported no upper GI toxicity; on
27 (18,9%), 36 (25,2%) and 28 (19,5%) patients were
observed respectively grade 1, 2 and 3 toxicity. No grade
4 toxicity was recorded.
Fiftyone patients discontinued radiotherapy and 9 did not
complete it, none of them because of GI toxicities.
Analizing VDose for upper GI toxicity grade ≥ 2 on DVHs,
small bowel loops V31.7, bowel bag V32.7, liver V35.6 Gy
and stomach V31.5 Gy resulted as the parameter which
most influenced upper GI toxicity (p<0.05). Univariate
analysis for ≥G3 grade upper GI toxicity for all structures
was not statistically significant (p>0.05). Univariate
analysis showed no impact of surgery on upper GI toxicity
while female sex and concomitant chemotherapy were
associated with likely upper GI toxicity. Multivariate
logistic model showed liver V35.6 as best and unique
predictor of GI toxicity grade ≥ 2 (p<0.01). Relation
between dose and toxicity is summarized in figure 1 as
empirical cumulative density function plot.
Conclusion