ESTRO 36 Abstract Book

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S675 ESTRO 36
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EP-1254 DVH analysis of radiotherapy of upper
gastrointestinal tumours: a model to predict toxicity.
G.C. Mattiucci1, L. De Filippo1, N. Dinapoli1, L. Boldrini1,
S. Chiesa 1, M. Bianchi1, R. Canna1, F. Cellini1, G.
Chiloiro1, F. Deodato2 , G. Macchia2, C. Indellicati1, D.
Pasini1, A.G. Morganti3, V. Valentini1
1 Università Cattolica del Sacro Cuore -Policlinico A.
Gemelli, Radiotherapy, Rome, Italy
2 Fondazione di Ricerca e Cura “Giovanni Paolo II”-
Università Cattolica del Sacro Cuore, Radiotherapy Unit,
Campobasso, Italy
3 Department 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
In this investigation on patients treated for upper GI
cancer, we recommend that V35.6 Liver (relative) should
be held to < 22% in order to get upper GI toxicity grade ≥2
probability below 15%. Further investigations should be
done in order to observe significant dosimetric evaluation
in patients with grade≥3 toxicity.
EP-1255 Early clinical results for esophageal
brachytherapy using a novel multi-balloon HDR
applicator
A.S. Taggar 1, G.N. Cohen1, P.J. Brady1, J.J. Cuaron1, A.
Wu1
1Memorial Sloan Kettering Cancer Center, Radiation
Oncology, New York, USA
Purpose or Objective
Management of superficial primary and locally recurrent
esophageal cancer (EC) in medically inoperable patients is
complex. Endoluminal high-dose-rate (HDR)
brachytherapy (BT) has shown mixed results in terms of
toxicity and local control (LC). In this study, we assessed
the outcomes and toxicities in a set of patients treated in
a consistent fashion with a novel multi-balloon HDR
applicator (E-app) using CT-based planning.
Material and Methods
Five patients were treated with the E-app between
November 2015 and August 2016 in a single institution.
Their records were reviewed retrospectively under
institutional ethics board approval. All patients were
treated with HDR brachytherapy using the E-app and 3D
CT-based treatment planning, and received a total of 15
Gy in 3 weekly fractions prescribed to tumor volume. All
treatments were completed as planned. Four patients had
distal esophagus/GE junction tumors, and one patient had
mid-thoracic tumor. For one patient who presented with
squamous cell (SC) and another with and neuro-endocrine
(NE) histology, BT was the primary treatment. Three
patients had adenocarcinoma histology and were
previously treated with primary chemo/radiotherapy
(CRT); two had residual disease after primary CRT and one
presented with recurrence 8 years after initial treatment
with CRT. Two patients with residual disease received
concurrent Capecitabine, whereas all others were treated
with BT only.
Results
Patients’ median (range) age and KPS at the time of BT
were 76.6 years (66.0–87.6) and 80 (40–90), respectively.
Median length of treatment was 7.0 cm (5.5–9.0 cm).
Median dose to the hottest 0.3cc within defined
esophageal target volume (D0.3cc) was 34.5 Gy (31.8–36.6
Gy). D0.3cc and V 100 of esophagus outside target volume
were 14.7 Gy (9.1–21.9 Gy) and 0.8 cc (0.0–3.6 cc),
respectively. Median follow-up from BT was 6.1 months
(1.7–7.3 months). Observed toxicities included dysphagia
(2 patients, grade 1 and grade 2), esophagitis (1 patient,
grade 1) stenosis (1 patient, grade 1) and asymptomatic
necrosis within the target area (1 patient, prior treatment
with 50.4 Gy + FOLFOX chemotherapy); no grade 3 toxicity
was observed. Repeat biopsy at 3 months’ post BT was
done in 3 out of 5 patients: 2 (patients with SC and NE
histology) had no evidence of disease and one had
persistent disease. One patient developed metastatic
disease and died without endoscopic assessment or biopsy
after BT.
Conclusion
This is the first report of clinical outcomes using a novel
multi-balloon HDR brachytherapy applicator (E-App). The
E-App appears to provide a safe and effective method of
delivering high doses of radiation to localized esophageal
cancers. We observed low rate of toxicity with short
follow-up and promising clinical and pathological
responses in the settings of recurrent and residual
disease.