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6th ICHNO
6
th
ICHNO Conference
International Conference on innovative approaches in Head and Neck Oncology
16 – 18 March 2017
Barcelona, Spain
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identifies the side and site of lymphedema for the
purposes of intervention.
PO-112 Role for interim PET in patient selection for
dose escalation and boost volume definition in HNSCC?
J. Lynch
1
, A. Nisbet
2
, C. Clark
2
, S. Whitaker
3
, K. Wood
3
1
Maidstone & Tunbridge Wells NHS Trust, Oncology,
Maidstone, United Kingdom
2
St Luke's Cancer Centre, Medical Physics, Guildford,
United Kingdom
3
St Luke's Cancer Centre, Head & Neck, Guildford,
United Kingdom
Purpose or Objective
The aim of this prospective pilot study was to look at the
feasibility and clinical value of performing an interim
18
F-
FDG-PET-CT (iPET) in patients with head and neck
squamous cell carcinoma (HNSCC). The spatial stability of
the most FDG avid area of the tumour during treatment
and the correlation of the data provided by pre-
treatment, interim and post treatment scans with known
prognostic factors and early survival was assessed.
Material and Methods
Eligible patients included those undergoing primary
concomitant chemoradiotherapy (65Gy/30F) with weekly
Cisplatin for Stage III/IV SCC of the Oropharynx. HPV status
and smoking history was determined on enrolment. Each
patient underwent a contrast enhanced planning CT and
PET scan immobilised in the treatment position on
consecutive days prior to the start of treatment and then
again after 8 fractions of radiotherapy. A primary boost
volume was defined according to 50% of the SUVmax of the
tumour using the autocontouring function in the
treatment planning system. A margin of 3mm was applied
to this to provide a PTVboost.
Results
Eighteen patients (14M, 4F) fitting the above criteria were
recruited. Mean follow up is 20 months.
All patients completed their scans on schedule with the
exception of one patient due to machine breakdown. A
boost volume was successfully delineated on both pre- and
interim scans using the above method in all except 3
patients where the SUVmax was not sufficiently higher
than background on one or both scans to define an
accurate volume.
The SUVmax of the primary tumour on the initial scan was
higher in the p16 -ve and patients with a smoking history
of >10 years (Table 1). The results did not reach statistical
significance, however when the patients who were p16
+ve with a smoking history of >10years were excluded from
the p16 analysis then the difference between the positive
and negative patients was greater (p=0.052).
All except 3 patients showed a drop in SUVmax between
the pre- and interim scans. The volume of the PTVboost
reduced by an average of 49% between the two scans (29
– 100%). Two patients showed only very marginal increase
which did not subsequently lead to an increase in the size
of the PTVboost.
One patient showed a big rise in their SUVmax (9.7 to
19.6). The volume of their PTVboost therefore increased
by 99%. Their 12 week PET scan was deemed to show
complete response but the patient subsequently had a
local relapse 7 months after completion of treatment.
Conclusion
In comparison to other studies that have looked at the
value of an iPET in patients with HNSCC this was a more
tightly controlled study with a more homogenous group of
patients. The results suggest the PET characteristics do
correlate with known prognostic factors which has not
been documented previously. The dual role of the iPET for
identifying patients who may benefit from dose escalation
and defining a volume for a radiotherapy boost merits
further investigation.
PO-113 Dynamics of biological imaging parameters in
PW-MRI and FMISO-PET/CT during chemoradiation of
SCCHN
A. Bunea
1
, H. Bunea
1
, C. Stoykow
2
, L. Majerus
1
, N.
Wiedenmann
1
, M. Mix
2
, P. Meyer
2
, M. Bock
3
, A.L. Grosu
1
1
Universitatsklinik Freiburg, Klinik für
Strahlenheilkunde, Freiburg, Germany
2
Universitatsklinik Freiburg, Klinik für Nuklearmedizin,
Freiburg, Germany
3
Universitatsklinik Freiburg, Medizinphysik, Freiburg,
Germany
Purpose or Objective
Tumor hypoxia in squamous cell carcinoma of the head
and neck (SCCHN) is related to poor prognosis.
Reoxygenation during treatment leads to improved
radiosensitivity. Adaptation of radiotherapy planning may
allow for a more individualized treatment. The following
study seeks to detected the dynamics of hypoxia during
chemoradiation (RCTx) with FMISO PET/CT and correlated
to perfusion MRI (PWI) parameters.PWI parameters can be
correlated with tumor hypoxia and thereby have the
potential to serve as predictors of treatment failure. In
particular, the volume transfer constant between plasma
and interstitial space Ktrans is an indirect measure of the
capillary permeability and blood flow. High skewness of
Ktrans is shown to be associated with improved treatment
response, while tumors with low Ktrans have a poor
prognosis (Shukla-Dave et al., 2012). A rise of Ktrans
during RCTx is associated with a good response to
treatment.
Material and Methods
We conducted a prospective imaging study in patients
undergoing definitive RCTx (70 Gy, concomitant cisplatin)
for HNSCC: in weeks 0, 2 and 5, 3-Tesla-MRI and FMISO PET
were acquired. Tumor hypoxia was assessed in FMISO PET
2.5 h p.i. Gross tumor volume in MRI (GTVMRI) was defined
as the area of high signal on T2-weighted images using the
T1-weighted images for anatomic cross reference.
Perfusion parameters Ktrans was calculated from dynamic
T1-weighted MRI after contrast agent injection. MRI and
PET scans were matched using iPlan contouring tool (v.
3.0.0, BrainLAB AG). Hypoxic subvolume (HSV) of GTVMRI
was defined after normalization to the FMISO background
in the contralateral sternocleidomastoid muscle,
multiplied by 1.4. Volumetric parameters between weeks
0, 2 and 5 were compared and related to treatment
response in terms of local recurrence (LR) and stable
disease (SD). Statistical analysis was done with Spearman
correlation. Before t-test analysis, normal sample
distribution was confirmed with Shapiro–Wilk test.
Results
Between 2014 and 2015 10 male patients, treated for
SCCHN with RCTx, were included. All received a total dose
of 70 Gy. In total, 30 FMISO-PET/CT data sets and 27 MRI
data sets were obtained. Mean follow up (FU) was 14.6
months (4 - 28 months). In weeks 0-5, patients with LR
showed a mean Ktrans-decrease of 19%, whereas in weeks
0-2 an increase of SUVmax (57 %) was shown. Patients with
SD showed Ktrans-increase (36 %) and SUVmax-decrease (-
61 %). HSV diminished in all patients. The correlation was
significant between Δ GTVMRI and Δ Ktrans in week 0-2
(p=0.037) and between Δ SUVmax (week 0-5) and Δ Ktrans
(week 0-2), p=0.045.
Conclusion
As was previously shown we conclude that changes in
SUVmax are crucial in week 2. In our limited patient
cohort and the short FU, we found that an increase in
Ktrans might be related to improved outcome. Finding