6th ICHNO Abstract Book

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6th ICHNO page 39
6th ICHNO Conference
International Conference on innovative approaches in Head and Neck Oncology
16 – 18 March 2017
Barcelona, Spain
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Conclusion
The results of this survey demonstrate that despite the
recognised fundamental importance of H&NC research to
care quality, many UK oncologists have limited or no time
specifically allocated to this in their job plan. Many are
not actively recruiting to national or local/non-portfolio
trials, although there is willingness for greater
involvement. The results provide useful insights into the
constraints in H&NC research currently faced by clinicians
within the NHS, which will need to be addressed in order
to facilitate H&NC research in the future.
PO-081 Recurrence analysis in head and neck squamous
cell carcinoma treated with adjuvant EUD-based IMRT
S. Welz1, T. Schönle1, D. Thorwarth2, D. Zips3
1Eberhard Karls University Tübingen, Radiation Oncology,
Tübingen, Germany
2Eberhard Karls University Tübingen, Biomedical Physics,
Tübingen, Germany
3Eberhard Karls University Tübingen, Radiatio Oncology,
Tübingen, Germany
Purpose or Objective
Resected high-risk patients with squamous cell carcinomas
of the head and neck (HNSCC) experience local
recurrences in about 20% despite adjuvant radio- or
radiochemotherapy. There is a paucity of data concerning
the recurrence rates and sites in patients treated with
IMRT, especially when planned with a Monte-Carlo
algorithm based on an equivalent uniform dose (EUD)
approach. We analyzed our data in this respect.
Material and Methods
We included all HNSCC (oral cavity, oropharynx and
hypopharynx) patients from 2008 to 2012 who received a
resection and completed an adjuvant IMRT of 60 to 66 Gy
with or without a cisplatinum based chemotherapy. Follow
up visits were scheduled at least every 3 months including
CT scans. Recurrences were categorized as in-field,
marginal or ex-field.
Results
128 patients were included. Median follow-up was 24
months. 54% received adjuvant radiotherapy only, 46% had
radiochemotherapy. Locoregional control was 94% with 2%
only local, 2% local and nodal and 2% locoregional and
distant recurrence. Of the 8 local recurrences, 3 were in-
field, 4 were marginal and one was ex-field. Two-year
overall survival was 79%, disease-free survival was 86%.
Grade 1-2 acute toxicity occurred in 67% of the patients,
grade toxicity 3-4 in 30%.
Conclusion
Adjuvant radio- or radiochemotherapy using IMRT with an
EUD based prescription is safe. Recurrences occur mainly
in or close to the tumor bed.
PO-082 Correlation between HI, GI, CI and Size of
Metastases for Linac-Based High Dose SRT / SRS B. Tas1,
I.F. Durmus1, A. Okumus1, O.E. Uzel1
1Yeni Yuzyil University Medicine Faculty Gaziosmanpasa
Hospital, Radiation Oncology, Istanbul, Turkey
Purpose or Objective
To evaluate correlation between Heterogeneity Index
(HI), Gradient Index (GI), Conformity Index (CI) and size of
metastases for high dose Stereotactic
Radiotherapy/Radiosurgery (SRT/SRS) using Elekta Versa
HD® lineer accelerator with Agility® collimator system.
Material and Methods
Twelve patients with single metastases were used in this
study. For each of the patients, the target was defined on
CT-MR fused images. Agility® Multi Leaf Collimator
system’s features were used for patients treatment
planning. Minimum segment width adjusted 0.5cm, grid
spacing adjusted 0.2cm and statistical uncertainty
adjusted 1%. Patient’s treatment planning were
performed using Monaco5.1 ® treatment planning system
(TPS) with three or four non-coplanars 6 MV Flattening
Filter Free (FFF) beams by partial Volumetric Modulated
Arc Therapy (VMAT) tecnique for each patient. We
determined four different size of metasteses catagory
which are less than 0.5cc volume, between 0.5cc and 1cc
volume, between 1cc and 5cc volume and between 5cc
and 10cc volume. Also, five different plans were
performed for getting different HI for each patients and
maximum HI was restiricted 1.50.
Results
Correlations were determined between HI, GI, CI and size
of metastases. Also, new Plan Quality Index (pQI)
suggested for plan quality level of high dose Stereotactic
Radiotherapy/Radiosurgery (SRT/SRS) plans. The mean
lowest pQI was determined 6.60±0.3 for less than 0.5cc
metastases volume, 5.28±0.7 for between 0.5cc and 1cc
metastases volume, 4.57±0.2 for between 1cc and 5cc
metastases volume and 3.29±0.2 for between 5cc and 10cc
metastases volume.
Conclusion
Ideal one is the lowest GI and CI for good quality plan but
GI and CI are not giving plan quality level exactly one by
one. Therefore, we could determine plan quality level of
treatment with pQI. Also, pQI depends on significantly size
and HI of metastases especially for less than 1cc volume.
When the metastases size is larger than 5cc, size of
metastases and HI is losing its importance for pQI. Based
on the correlation between HI, GI, CI and size of
metastases we have decided that pQI should be ≤ 7.0 for
less than 0.5cc metastases volume, pQI should be ≤ 6.0 for
between 0.5cc and 1cc metastases volume, pQI should be
≤ 5.0 for between 1cc and 5cc metastases volume and pQI
should be ≤ 4.0 for between 5cc and 10cc metastases
volume for linac-based high dose Stereotactic
Radiotherapy / Radiosurgery (SRT/SRT).
PO-083 Adaptative radiotherapy for nasopharyngeal
carcinoma
L. Farhat1, W. Mnejja 1, T. Sahnoun1, F. Dhouib 1, J. DAOUD1
1EPS HABIB BOURGUIBA, Radiotherapy, SFAX, Tunisia
Purpose or Objective
Adaptative radiotherapy is a modification of the initial
radiotherapy plan during the radiation course to re-
optimize the treatment to take into account the anatomic
variation such as the tumor response and weight loss.