6th ICHNO Abstract Book

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6th ICHNO page 41
6th ICHNO Conference
International Conference on innovative approaches in Head and Neck Oncology
16 – 18 March 2017
Barcelona, Spain
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Glutamine delays oral mucositis in the head neck cancer
patients. Moreover, it reduces the frequency and duration
of grade 3 and grade 4 mucositis. More of the patients not
receiving glutamine developed severe malnutrition when
compared with those receiving this supplement, but there
were no differences in other outcomes such as
interruption of RT, hospitalization, use of opioid
analgesics, or death during RT. Glutamine may have a
protective effect during RT, reducing the risk and severity
of OM, preventing weight loss, and reducing the need for
nutritional support.
PO-086 Brachial plexus position reproducibility for head
and neck radiotherapy and it’s dosimetric impact
S. English1, A. Thompson1
1North Middlesex University Hospital, Radiotherapy,
London, United Kingdom
Purpose or Objective
Radiation-induced brachial plexopathy is a rare late
complication of radiotherapy(RT) that can cause
significant morbidity [1]. The Radiation Therapy Oncology
Group recommends limiting the brachial plexus (BP)
maximum dose to 60 to 66 Gray(2) Delineation of the BP
and any dose constraints are defined at the point of
radiotherapy planning. However, lack of reproducibility of
patient position during RT treatment for example due to
weight loss may lead to dosimetric uncertainties. The
purpose of this retrospective study was to determine any
change in position of the BP during head and neck RT
treatment in relation to it’s original planned position and
the dosimetric consequences of this.
Material and Methods
The study population consisted of 10 patients with
oropharyngeal squamous cell carcinoma (OPSCC)
treated with volumetric arc radiotherapy (VMAT) to a dose
of 65Gy in 30 fractions over 6 weeks. Prior to commencing
VMAT, patients underwent CT planning scan in a supine
position in a 9-point thermoplastic mask. The treatment
volumes and organs at risk (OAR) were delineated and a
plan created using Eclipse Planning System. Treatment
verification was achieved using weekly Cone Beam CT
(CBCT) and daily KV imaging. For this retrospective study
the brachial plexus position was delineated on each
weekly CBCT. The position of the brachial plexus and the
dose received was compared and re-calculated against the
original planning scan. This resulted in 6 CBCT scans or
data points for each of the 10 patients.
Results
The position of the BP varied on each weekly CBCT
throughout treatment compared to the original planning
scan. It’s most stable point was at the level of C5/C6 while
most variation in position was observed around the T1
level. The results demonstrate an average dose increase
of 4% to the minimum and mean brachial plexus dose over
the course of the treatment equivalent to 2.6Gy.
Conclusion
VMAT allows us to plan and deliver high dose RT to achieve
maximum Planning Target Volume (PTV) coverage whilst
OAR dose constraints. The extent of OPSCC at both the
primary site and nodal levels treated with radiotherapy
impacts the maximum dose to the brachial plexus.
However, any loss of reproducibility of patient position
during RT may lead to uncertainty of dose delivered to
both PTV and OAR. Therefore, a dose constraint to the BP
may be exceeded. A recent study by Chen et al. (3)
suggested a dose-response relationship for the
development of brachial plexopathies with a 1.39 times
greater odds ratio of developing symptoms with each 1Gy
increase in the maximum BP dose.
Our small study suggests that the actual dose received by
the BP may be higher than planned due to it’s variation in
position throughout treatment. This may lead to increased
risk of brachial plexopathy in this patient population. In
order to avoid this risk there are a number of solutions
that can be considered including; lower dose constraints
on the brachial plexus, a margin on the BP volume to
account for any positional change or adaptive planning
again to account for any positional change.
PO-087 Adaptive 18F-FDG-PET-guided reirradiation for
recurrent and second primary head and neck cancer
J. Schatteman1, D. Van Gestel2, D. Berwouts1, W. De
Gersem3, I. Goethals1, L. Olteanu 3, S. Rottey4, T.
Vercauteren3, W. De Neve3, F. Duprez3
1Ghent University Hospital, Nuclear medicine, Ghent,
Belgium
2Jules Bordet Institute, Radiation oncology, Brussels,
Belgium
3Ghent University Hospital, Radiation Oncology, Ghent,
Belgium
4Ghent University Hospital, Medical Oncology, Ghent,
Belgium
Purpose or Objective
To evaluate feasibility, disease control, survival and
toxicity after adaptive 18F-FDG-positron emission
tomography (PET) guided radiotherapy in patients with
recurrent and second primary head and neck squamous
cell carcinoma (HNSCC).
Material and Methods
A non-randomized prospective trial investigated the
feasibility of adaptive radiotherapy ± concomitant
cetuximab in 10 patients with recurrent (n=5) and second
primary (n=5) HNSCC. A primary endpoint of the study was
to achieve a 2-year survival free of grade ≥3 late toxicity
in ≥30% of patients. Three treatment plans based on 3 pre-
and pertreatment PET/CT scans were consecutively
delivered in 6 weeks. The range of dose painting was 66.0-
85.0 Gy in the dose-painted tumoral volumes in 30
fractions with fraction doses delivered to the tumor
and/or positive lymph nodes of 2.2-3.5 Gy, 2.2-2.5 Gy and
2.2-2.5 Gy during fractions 1-10, 11-20 and 21-30,
respectively. Patients were treated with static beam IMRT
(n=6) or helical tomotherapy (n=4). If multidisciplinary
decision for concomitant systemic therapy was taken,
patients received a cetuximab loading dose (400 mg/m²)
one week before start of radiotherapy (RT), followed by
weekly doses of 250 mg/m² up to 6 times concomitant to
RT. Twenty patients were planned to be recruited.
Results
Due to a slow accrual the study was terminated after the
tenth patient. One patient did not complete the
prescribed treatment course because of arterial bleeding
during radiochemotherapy.
Median dose of the initial RT was 67.6 Gy. Median time
interval from initial RT to reirradiation was 6.3 years.
Median follow-up time was only 5.2 months, reflecting the
poor overall survival. One-year locoregional and distant
control were 38% and 76%, respectively. Overall and
disease-free survival at 1 year were 30% and 20%,
respectively (Figure 1).
No grade 4 or 5 acute toxicity was observed in any of the
patients, except for arterial mucosal bleeding in one
patient. Three months after radiotherapy, grade 4
dysphagia and mucosal wound healing problems were
observed in 1/7 and 1/6 of the patients, respectively.
Grade 5 toxicity (fatal bleeding) was seen in 2 patients,
respectively at 3.8 and 4.1 months of follow-up. Late
toxicity until 1 year of follow-up could only be assessed in
2 patients (Table 1). Data on 2-year grade ≥3 toxicity-free
survival is not yet available; however, since only 20% of