ESTRO 36 Abstract Book

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S587 ESTRO 36 2017
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patients over a longer follow up before dWMRI can be
utilised in clinical practice.
EP-1076 toxicity of concomitant chemotherapy and
IMRT in locally advanced OPSCC: sequential vs SIB
technique
G. Abate1, F. De Felice1, A. Galdieri1, G. Gravina2, F.
Marampon 3, D. Musio1 , V. Tombolini1
1 Policlinico Umberto I- “Sapienza” University of Rome,
radiotherapy, Roma, Italy
2 University of L'Aquila, Department of Biotechnological
and Applied Clinical Sciences- Laboratory of
Radiobiology, L'Aquila, Italy
3 University of L’Aquila-, Department of Biotechnological
and Applied Clinical Sciences- Laboratory of
Radiobiology, L'Aquila, Italy
Purpose or Objective
Concurrent radiochemotherapy is the standard of care for
locally advanced oropharingeal squamous cell carcinoma
(OPSCC) patients. Due to a substantial locoregional
recurrence rate especially in human papilloma virus (HPV)
negative disease, an improvement in treatment outcome
is desirable.
Treatment intensification with radiation dose escalation
could represent a valid option by applying accelerated
radiotherapy with higher dose for fraction and non-
uniform dose distribution with simultaneous integrated
boost (SIB). Even if radiobiological and clinical data
suggest that accelerated fractionation with higher dose
per fraction given in GTV may produce better locoregional
control, a higher toxicity is expected especially with
concomitant platinum 100 mg/mq based chemotherapy.
A comparison between sequential IMRT (S-IMRT) and SIB-
IMRT was planned. The aim was to evaluate the
tolerability and safety of SIB regimen in HPV negative
patients with locally advanced OPSCC
Material and Methods
Patients with histologically proven HPV negative OPSCC,
staged T3-4 with or without involved lymph nodes at
diagnosis, who received primary CRT, were included. S-
IMRT was defined as radiotherapy equivalent to 70 Gy (2
Gy/fraction). SIB-IMRT was administered to a total dose
of 67.5 Gy (2.25 Gy/fraction) to high dose volume and
60 (2 Gy/fraction) and 54 Gy (1.8 Gy/fraction) to high risk
and low risk volumesrespectively..
Fusion CT–MR imaging with a deformable registration
software was performed to accurately localize target
volumes and organs at risk.
Concomitant cisplatin (100mg/m2 on day 1 and day 22 day
of treatment) was used.
Results
A total of 46 patients (31 males, 15 females) with
a median age of 64 years (range 41-75) were examined
between February 2009 and March 2016. All patients
completed the programmed CRT treatment. No patients
suspended planned chemotherapy and all patients
received the IMRT prescribed total dose. No severe life
risking complications occurred and no significant
differences between S-IMRT and SIB-IMRT were observed
in term of major acute toxicities. Details are shown in
table 1
Conclusion
Our data shows that IMRT-SIB with 2.25 Gy/fraction with
concurrent platinum-100- based chemotherapy is a safe
treatment approach without increasing toxicities. This
regimen is therefore acceptable for the therapy of locally
advanced oropharyngeal cancer and patients with poor
prognosis as HPV negative OPSCC could benefit from it. A
longer follow up is needed to fully evaluate late toxicity
and survival.
EP-1077 Predictive modeling for radiation-induced
acute dysphagia in head and neck cancer patients.
D. Alterio1, M. Gerardi1, L. Cella 2, V. D'Avino2, G. Palma2,
D. Ciardo1, E. Rondi3, A. Ferrari1, M. Muto4, R. Spoto4, R.
Pacelli 5, R. Orecchia6, B. Jereczek7
1European Institute of Oncology, Radiation Oncology,
Milan, Italy
2National Council of Research, Biostructures and
Bioimaging, Naples, Italy
3European Institute of Oncology, Medical Physics, Milan,
Italy
4European Institute of Oncology - University of Milan,
Radiation Oncology -Oncology and Hemato-oncology,
Milan, Italy
5Federico II- University school of Medicine, Advanced
Biomedical Sciences, Naples, Italy
6European Institute of Oncology - University of Milan,
Medical Imaging and Radiation Sciences - Oncology and
Hemato-oncology, Milan, Italy
7European Institute of Oncology - University of Milan,
Radiation Oncology - Oncology and Hemato-oncology,
Milan, Italy
Purpose or Objective
To explore dosimetric predictors of acute dysphagia in
head and neck (H&N) cancer patients (pts) treated with
definitive radiotherapy (RT). We prospectively examined
correlation between doses to swallowing-associated
structures and acute radiation-related side effects, in
terms of dysphagia and percutaneous endoscopic
gastrostomy tube (PEG) requirement.
Material and Methods
We analyzed all consecutive not previously treated pts
with H&N cancer who underwent RT at our Department
between May 2010 and March 2011. Exclusion criteria
were: baseline dysphagia (functional dysphagia or enteral
nutrition) and previous surgery in the H&N region. A
nutritional standardized step-wedge protocol was applied.
Dysphagia (grade ≥3 according to CTCAE v4.0) and
indication to PEG insertion were classified as acute
toxicity events. Ten swallowing-related structures were
considered for the analysis: pharyngeal axis, base of
tongue, constrictor muscles (superior, middle and
inferior), cricopharyngeal muscle, soft palate, cervical
esophagus, oral cavity and supraglottic larynx. Dosimetric
parameters included mean dose (Dmean), near maximum
dose (D2%) and the percentage volume exceeding X Gy
(Vx) evaluated in 5-Gy steps. The correlation of clinical
information along with swallowing-related structure dose
parameters related to acute toxicity events was analyzed
by means of Spearman’s rank correlation coefficient (Rs).
Multivariate logistic regression method using resampling
methods (bootstrapping) was applied to select model
order and parameters for normal tissue complication
probability (NTCP) modeling. Model performance was
evaluated through the area under the curve (AUC) of the
receiver operating characteristic (ROC) analysis.
Results
Patient and treatment characteristics are summarized in
Table 1. Two pts required PEG, 3 pts had grade 3
dysphagia and 4 pts had both PEG and grade 3 dysphagia.
A strong multiple correlation between dosimetric
parameters was found. Intra-organ dosimetric parameters
were strongly correlated as well as inter-organ dosimetric
parameters. Accordingly, the highly correlated variables