ESTRO 36 Abstract Book

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S579 ESTRO 36 2017
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The BTVATA was bigger than the GTV40%SUV (17 vs. 15 cc) but
the difference was not statistically different (p> 0.05), the
CI was 0.8 and the DICE was 0.2.
Table 1. Tumour Volumes defined by the three different
methods.
GTV
Mean Volume
(cc) Ranges
Standard
Deviation
GTV ST 21.4 4.5 –
66.3
±16.0
GTV 40%SUV 14.7 1.3 – 58.5 ±13.7
GTV TATA 17.2 1.5 – 61.5 ± 12.8
Conclusion
The proposed adaptive thresholding algorithm resulted
robust and reproducible in the clinical context of head and
neck tumours. The tumour volumes obtained by the
algorithm were a part of the GTVST and were similar to
GTV 40%SUV. This tumour volume could allow the delineation
of a BTV for dose escalation in head and neck cancer
treated with IMRT-SIB.
EP-1060 Analysis of failure patterns and prognostic
factors after postoperative IMRT for buccal cancer
Y.W. Lin1, L.C. Lin1
1 Chi Mei Medical Center, Department of Radiation
Oncology, Tainan, Taiwan
Purpose or Objective
Squamous cell carcinoma (SCC) of buccal mucosa has a
high incidence of locoregional failure. Its aggressive
behavior and the change of lymphatic and vascular
drainage after surgery make the design of radiotherapy
difficult. The aim of this study is to analyze failure
patterns and prognostic factors in patients with locally
advanced buccal cancer after postoperative intensity
modulated radiotherapy (IMRT).
Material and Methods
Between January 2007 to October 2012, 84 patients with
histological confirmed SCC of buccal mucosa underwent
surgery followed by postoperative IMRT were
retrospectively analyzed.. All patients were stage III/IV
buccal cancer. The high-risk clinical target volume (CTV)
covered the surgical tumor bed and ipsilateral or bilateral
upper neck. The median dose to high-risk CTV was 60Gy.
Analyzed end-points were overall survival (OS), local
recurrence-free survival, loco-regional recurrence-free
survival, supra-mandibular notch recurrence-free survival,
distant metastasis-free survival, prognostic factors and
patterns of failure.
Results
The median follow up was 51 months (range, 2-112
months). The first recurrent sites were local tumor bed
(17 patients) with or without regional/distant recurrence.
The median time from treatment completion to first
locoregional recurrence was 7.3 months. Of the 17
patients with local recurrence, 11 exhibited the supra-
mandibular notch recurrence; most were classified as
marginal failure. The estimated 4-year local failure-free,
locoregional failure-free, distant metastasis-free and
overall survival rates were 72%, 63.3%, 85.9% and 68.8%.
In multivariate analysis, lymphovascular invasion (P =
0.002), N2 disease (P = 0.003), and ratio of tumor
thickness to tumor size larger than 1/3 (P = 0.014) were
independent prognostic factors for overall survival.
Patients received tumor excision with maxillectomy was a
predictive factor for the development of supra-mandibular
notch recurrence.
Conclusion
SCC of buccal mucosa is a highly aggressive form of oral
cavity cancer with a high locoregional failure rate and
most locoregional recurrences led to lethal events. Design
of postoperative IMRT for buccal cancer, especially CTV
delineation, based on failure patterns and
clinicopathological prognostic factors might transfer into
better disease control.
EP-1061 Towards a validated Decision Aid Tool for
advanced larynx cancer patients
A.J. Berlanga1, M. Petersen2, F. Hoebers1, S.
Delbressine 1, M. Van den Breke 2,3,4, P. Lambin1
1Maastro Clinic, GROW School for Oncology and
Developmental Biology- Maastricht University Medical
Centre, Maastricht, The Netherlands
2The Netherlands Cancer Institute, Department of Head
and Neck Surgery and Oncology, Amsterdam, The
Netherlands
3Academic Medical Center, Department of Oral and
Maxillofacial Surgery, Amsterdam, The Netherlands
4University of Amsterdam, Institute of Phonetic Sciences,
Amsterdam, The Netherlands
Purpose or Objective
Advanced larynx cancer patients may be eligible for more
than one treatment: laryngectomy, radiotherapy,
chemoradiation, or combinations thereof. These
treatments have a distinct impact on quality of life (e.g.
disfigurement, speech, swallowing problems), and
outcomes depending on TNM-classification.
To empower these patients to participate in shared-
decision making, we are creating a web-based Patient
Decision Aid Tool (PDA, . The
goal is help patients to understand treatment options and
support clinicians to gain perspective of patients’
preferences.
Material and Methods
The PDA was validated following the International Patient
Decision Aid Standards (IPDAS). First, a prototype was
created considering literature and input from an
interdisciplinary group. A mixed-method (interview, 5-
Likert questionnaire) was used to identify patients’
decisional needs, and to evaluate if the tool was clear and
perceived as useful for shared-decision making.
Clinicians (N=8) and patients (N= 12) from two hospitals
were included.
Results
Patients and clinicians agreed on patient’s difficulty to
recall spoken information and understand risk
probabilities. They mentioned the need of information
about treatment options, side effects, and effectiveness.
Patients asked for information about procedures before
and after treatment.
Patients preferred information that is simple, visual, and
in small chunks. Clinicians preferred information adapted
to patient’s psychosocial level.
Patients were positive about the PDA. All criteria
(satisfaction, effectiveness, clarity, usability, usefulness,
intention use) had a median (IQR) of 4 ('agree”). Patients
asked for simpler terms, information on psychological
effects and the 'no treatment option”.
Considering these results, a new version was created
(Fig.1). It is a visual tool, containing video interviews with
clinicians and animations to explain the treatments.
This version will be validated by clinicians and patients for
comprehensibility and usability. Results will be considered
to create a final version. Thereafter, we will evaluate its
impact on shared decision-making in a multi-center
setting.