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3rd ESTRO Forum 2015 S619
between LC and D
95%
and
D
98%
, but a strong dependence on
D
mean
(p=0.0274) and EUD (p=0.0483) was noticed.
Fig. 1. The correlation between loco-regional control and D
95%
(a),
D
98%
(b),
D
mean
(c) and EUD (d). Values of D
95%,
D
98%,
D
mean
and EUD are normalized to the prescribed dose.
a.
b.
c.
d.
Due to the small number of patients, multivariate analysis of
correlation between LC and patients' clinical and dosimetric
data was not possible, and further studies are needed to
identify the most predictive variable.
Conclusions: LC for HNC patients treated with SIB IMRT
significantly correlates with pathology, stage and the use of
concomitant chemotherapy. Treatment plan dosimetric data
such as D
mean
and EUD appear to be useful predictors of LC for
this group of patients.
EP-1138
Reirradiation, cetuximab and itraconazole in locally
recurrent and unresectable head and neck cancer
D. Milanovic
1
, A.L. Grosu
1
, M. Henke
1
1
Universitätsklinik Freiburg, Department of Radiation
Oncology, Freiburg, Germany
Purpose/Objective: Locoregional inoperable recurrence of
previously irradiated head and neck carcinoma (HNC) remain
a therapeutic challenge. In our previous study, we combined
re-RT with cetuximab, with the aim to inhibit epidermal
growth factor receptor EGFR and consequently increase
tumor radiosensitivity, but this therapeutic approach did not
influence patient survival in the comparison to standard
therapy. Hedgehog (HH) signaling pathway, which plays
important role in embryogenesis, carcinogenesis und
radioresistance, can mediate therapeutic resistance to EGFR
targeted therapies. Itraconazole is well known antimicotic
agent which inhibits HH signaling. In patients with advanced
basal cell carcinoma, itraconazole inhibited this pathway and
caused promising clinical response. We propose that
inhibition of HH signaling with itraconazole will avoid
development of resistance to cetuximab and that
simultaneous inhibition of these two pathways which
interfere with radioresistance may lead to better tumor
response and consequently prolonged survival in patient with
recurrent HNC treated with re-RT.
Materials and Methods: Between March and November 2014,
we reirradiated (59.4 Gy, 5 X 1.8 Gy/Week) 5 patients with
inoperable, previously irradiated, recurrent HNC. Cetuximab
was given initially at 400 mg/m
2
two days prior to re-RT and
weekly (250 mg/m
2
) thereafter. Patients were treated with
first dose itraconazole (100 mg) two days prior to re-RT and
continued to take this drug daily two weeks after finishing re-
RT.
Results: Itroconazole did not increase toxicity of re-RT and
cetuximab expecting for induction of acne-like skin rash. 3
patients developed grade III and 1 grade II of this
complication. Until now, three patients had a first follow-up
investigation – two partial responses (1 patient with grade I
and one with grade III skin rash) and 1 with grade III and one
stable disease were documented.
Conclusions: Promising antitumor responses were observed.
To determine if this therapeutic strategy may influence
survival in patients with recurrent HNC treated with re-RT,
larger clinical studies are necessary.
EP-1139
Hypofractionated radiation therapy for nasopharyngeal
carcinoma: preliminary results
A. Boukerche
1
, S. Boumediene
1
, E. Mous
1
, F.Z. Boudinar
2
, A.F.
Dali-Youcef
2
1
Faculty of Medicine University of Oran, Radiation Oncology,
Oran, Algeria
2
Faculty of Medicine University of Oran, Medical Oncology,
Oran, Algeria
Purpose/Objective: To evaluate the efficacy and toxicity in a
group of patient with non-metastatic nasopharyngeal
carcinoma (NPC) treated with a hypofractionated radiation
therapy with or without chemotherpy.
S620 3rd ESTRO Forum 2015
Materials and Methods: From January 2011 to December
2013, 155 patients (97 male / 58 female) who had
histopathologically confirmed NPC treated in our department
with definitive-intent RT to a dose of 54 – 57 Gy (3 Gy daily
fraction) for nasopharyngeal tumour and positive neck lymph
nodes. The dose for the prevention irradiation of negative
neck lymph nodes was 36 – 51 Gy (3 Gy daily fraction).
Results: Mean age was 44.9 ± 1.1 years (Range 16-81). Stage
I, II, III, IVA and IVB (UICC 2009) were 7, 32, 40, 51 and 25
respectively. 118 patients received induction chemotherapy
platinum-based. Commonest adverse effects (NCI-CTC 4.0)
were: mucositis, dysphagia, and dermatisis. Grade 3 or 4
mucositis, dysphagia, dermatisis occurred in 16 cases (10.3%),
15 cases (9.7%) and 4 cases (2.6%) respectively. Response
rate of 154 patients were (1 patient was refused evaluation):
complete response 65.6%, Partial response 24.1%, stable
disease 7.1% and progressive disease 3.2%. With median
follow-up of 18 months, 10 and 15 patients were presented
locoregional recurrence and metastasis respectively. The
locoregional control (LRC), Metastasis free survival (MFS),
disease free survival (DFS) and overall survival (OS) rates at
one year were: 95.8% (±1.8%), 89.3% (±2.6%), 85.2 % (±3.1%)
and 93.9% (±2.1%), respectively.
Conclusions: Preliminary findings using a hypofractionated
scheme is a feasible option in the treatment of NPC (an
effective regimen with an acceptable safety profile).
However, an important number of patients and a longer
follow-up are necessary to better appreciate the efficacy and
the toxicity outcome (late effect) of this scheme.
EP-1140
Dosimetric evaluation of jaw tracking in VMAT of head and
neck cancers in True beam STx linear Accelerator
S. Maruthu Pandian
1
, S. Karthikeyan
1
1
BGS Global Hospitals, Radiation Oncology, Bangalore
Karnataka, India
Purpose/Objective: Currently, during the delivery of the
Rapid Arc® (RA)/Volumetric Modulated Arc Therapy (VMAT)
plan, the jaws are fixed allowing the possibility of radiation
leaking in-between leaves and in-between the leaves gaps
from opposite pairs. The purpose of this work is to evaluate
the potential improvement in Rapid Arc plans dosimetry when
plan delivery allows for jaw tracking. This work represents
one of the initial attempts to assess the usefulness of
evaluating normal tissue dose reduction in dynamic VMAT on
the True beam STx platform by tracking the multi-leaf
collimator (MLC) apertures with the accelerator jaws.
Materials and Methods: We use the Eclipse (version 10.4) and
Truebeam STx linear accelerator which allows jaw tracking
during VMAT delivery for both the X and Y jaws. We
considered, Brain, Head & Neck patients. We set the
collimator between 15
o
and 30
o
and generate plans with and
without jaw tracking for comparison. Special attention is
given to the low dose regions where more noticeable
differences were expected.Clinical radiation treatment plans
for Brain, Head and Neck patients were converted to plans
with the jaws tracking. Each plan without jaw tracking were
planned to obtain target coverage within 1% of that in the
original jaw tracking plan. The new plans were compared to
the original plans in a Varian Eclipse treatment planning
system (TPS). Reduction in normal tissue dose was evaluated
in the new plan by using the parameters V5, V10, and V20 in
the cumulative dose-volume histogram for the following
structures: Brainstem, Spinal cord, Parotids. Cochlea, Oral
Cavity, Larynx, Mandible In order to validate the accuracy of
our beam model, MLC transmission measurements were made
and compared to those predicted by the TPS.
Results: The greatest change between the original plan and
new plan occurred at lower dose levels. The reduction in V20
was never more than 3.7% and was typically less than 1% for
all patients. The reduction in V10 was never more than 6.9%
and was typically less than 1.5% for all patients. The
reduction in V5 was 1.4% maximum and was typically less
than 0.5% for all patients. The variation in normal tissue dose
reduction was not predictable, and we found no clear
parameters that indicated which patients would benefit most
from jaw tracking. Our TPS model of MLC transmission agreed
with measurements with absolute transmission differences of
less than 0.1 % and thus uncertainties in the model did not
contribute significantly to the uncertainty in the dose
determination
Conclusions: The amount of dose reduction achieved by
collimating the jaws around each MLC aperture in VMAT
appears to be similar and not more than 2%. Currently we are
analysing more plans for other sites and with other
geometries to improve the statistical significance of our
conclusion.
EP-1141
þ-tubulin II expression as a predictive marker for response
to taxane-based chemotherapy in head and neck cancers
E. Wasilewska-Tesluk
1
, S. Nawrocki
2
, E. Cieslak-Zeranska
1
1
University of Varmia&Masuria Faculty of Medical Sciences,
Oncology Dep., Olsztyn, Poland
2
University of Silesia, Oncology Dep., Katowice, Poland
Purpose/Objective: The aim of the work was to assess the
significance of beta-tubulin II (βT-II) expression as a
predictive marker for clinical response to neoadjuvant TPF
chemotherapy (Docetaxel, Cisplatin, Fluorouracil) in locally
advanced squamous cell head and neck cancers (LASHNC).
Materials and Methods: A group of 31 patients, without
distant metastasis, with LASHNC in clinical stage III or IV of
disease, not qualified primary for concurrent chemoradiation
because of large primary tumor or bulky neck lymph nodes
metastases, was analyzed retrospectively. In the therapy, 2–3
cycles of neoadjuvant TPF chemotherapy were used,
followed by radiotherapy or chemoradiotherapy in all
patients. The tumor response to neoadjuvant therapy was
assessed according to RECIST vs 1.1, based on the results of
facial skeleton CT scanning before and after the
chemotherapy. Using immunohistochemical method, the
presence of βT-II in the tumor tissue was assayed in paraffin-
embedded, archive tissue material collected from the
patients before the start of the therapy. A computer analysis
of IHC reaction image was performed using DensitoQuant
software (3DHISTECH, Hungary). The high expression
threshold was defined as presence of >17% of moderate and
strong reactions in the specimen. The clinical response to
TPF chemotherapy as categorized according to RECIST and by
percentage of measurable lesions regression, in the context
of level of βT-II in cancer cells was analyzed.
Results: 12 specimens (38.7%) were classified to high and 19
specimens (61.3%) to low protein expression group. Partial
regression (PR) of lesions after neoadjuvant chemotherapy