6th ICHNO Abstract Book

52 / 79

6th ICHNO page 53
6th ICHNO Conference
International Conference on innovative approaches in Head and Neck Oncology
16 – 18 March 2017
Barcelona, Spain
__________________________________________________________________________________________
lymphoscintigrams were scored as non-SLNs when SPECT-
CT was added. There were 4 false negative SLN biopsy
procedures in this cohort.
Conclusion
The addition of SPECT-CT to planar lymphoscintigraphy is
recommended for the identification of more (positive)
SLNs and better topographical orientation for surgery in
sentinel lymph node biopsy for early stage oral cancer.
PO-110 Analysis of loco-regional failures after IMRT for
HNSCC using deformable image registration
R. Zukauskaite1, C.R. Hansen1, J. Johansen1, C. Grau2, J.
Overgaard3, C. Brink1
1Odense University Hospital, Department of Oncology,
Odense, Denmark
2Aarhus University Hospital, Department of Oncology,
Aarhus, Denmark
3Aarhus University Hospital, Department of Experimental
Clinical Oncology, Aarhus, Denmark
Purpose or Objective
Most failures after curative radiotherapy for head and
neck squamous cell carcinoma (HNSCC) appear loco-
regionally. Moreover, IMRT may increase the risk of
marginal failures due to the high conformity.
Identification and analysis of possible points of loco-
regional recurrence (LRR) in relation to treatment volume
may pave the way for improved treatment planning and
outcomes. The aim of this project was to analyze loco-
regional recurrence pattern after curative IMRT.
Material and Methods
457 patients with larynx, pharynx and oral cavity HNSCC
were consecutively treated with primary IMRT from 2006-
2012 in one institution. The majority of patients had loco-
regionally advanced disease. Most patients were treated
with curatively intended primary IMRT with 66-68 Gy in 6
fractions weekly with concomitant Nimorazol and
Cisplatin according to DAHANCA guidelines. Elective
therapeutic levels were treated to 50 Gy. All CT or
PET/CT-confirmed loco-regional recurrences were
identified, and the diagnostic CTs were deformable
registered with planning CTs. Four different approaches to
define possible points of LRR origin (PO) were identified:
two by independent observers, mass mid-point (MMP), and
a point with maximal surface distance (MSD). Points were
further analyzed in relation to clinical high-risk treatment
volume (CTV1) and planned treatment volume (95%
isodose of high-risk volume).
Results
Median follow-up was 41 months (range 2-107). 290
patients (63%) remained recurrence-free and 167
developed some sort of failure. The three-year loco-
regional control rate was 68%. 70 patients with 105 CT
verified LRR were further analysed. 35, 19 and 16 pts had
recurrences in T, N or both T and N sites, respectively.
Median distances between the four different ways to
estimate POs in the x, y and z axis were 3.0, 3.0 and 8.2
mm, respectively. The distances between all four POs to
CTV1 and the 95% isodose curve were consistent. 41% of
POs were within CTV1 (Figure 1.) and 58% were covered
by the 95% isodose curve. In 13 cases, LRRs were outside
the treatment volume. LRR identified 5 mm outside the
CTV1 accounted for 13.3% of all LRR and may represent
marginal recurrences in the present study.
Conclusion
We confirmed that the majority of loco-regional
recurrences appear in the high dose volume. This is
consistent using four different recurrence identification
approaches. The current data may differ between centres
using larger treatment margins and this is currently under
investigation.
PO-111 Dermal backflow: NIRFLI pattern associated
multimodality therapy in patients with oropharynx
cancer
S. Naqvi1, I. Tan2, J. Rasmussen2, M. Aldrich2, J. Morrow2,
A. Blanco3, C Gutierrez4, K. Jain1, E. Sevick-Muraca2, R.
Karni 1
1The University of Texas Health Science Center- Houston,
Otorhinolaryngology- Head and Neck Surgery, Houston,
USA
2The University of Texas Health Science Center- Houston,
Center for Molecular Imaging, Houston, USA
3The University of Texas Health Science Center- Houston,
Radiation Oncology, Houston, USA
4The University of Texas Health Science Center- Houston,
Physical Medicine and Rehabilitation, Houston, USA
Purpose or Objective
Lymphedema is a ubiquitous side effect of oropharynx
cancer treatment and is characterized by swelling and
fibrosis which leads to a deterioration in quality of life.
Currently there is limited understanding about how to
properly diagnose and treat head and neck lymphedema.
Our team has previously described a novel imaging system
for the identification of aberrant lymph vessel flow of the
cervical region in patients with Head and Neck Cancer.
Material and Methods
Following intraoral and intradermal injections of
indocyanine green, lymphatic anatomy was visualized
using near-infrared fluorescence lymphatic imaging
(NIRFLI). Six oropharynx cancer patients were imaged
prior to treatment, and then followed up for thirty weeks.
One subject received neither neck surgery nor radiation,
one patient had bilateral therapeutic-range neck radiation
without neck dissection, two patients had unilateral neck
dissection with post-operative radiation to the operated
neck alone, one patient had unilateral neck dissection but
post-operative radiation applied to both sides of the neck,
and one patient had bilateral neck dissections and
bilateral post-operative neck irradiation.
Results
Lymphatic vessels were readily visualized in all six
subjects (12 necks). All five necks that received both neck
dissection and post-operative therapeutic-dose radiation
(>56Gy) exhibited dermal backflow (5/5). In the necks
that received neither surgery nor radiation, dermal
backflow was not observed (4/4). One of three necks that
received radiation alone without neck dissection also
developed dermal backflow.
Conclusion
Post-operative radiotherapy is strongly associated with
the development of dermal backflow. Likewise, treatment
de-escalation in early stage oropharynx cancer which
spares a therapeutic dose of radiation to the contralateral
neck also preserves the native lymphatic function. It is our
contention that NIRFLI is an emerging imaging modality for
the identification of aberrant lymphatic backflow
following treatment of oropharynx cancer and specifically