ESTRO 36 Abstract Book

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S1011 ESTRO 36
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plan was recalculated on the CBCT for the first and last
fractions. Comparisons were made in terms of changes in
CTV volumes over the course of treatments. Bladder,
bowel and rectum dose was assessed using V30Gy and
V40Gy.
Results
A total of 100 CBCTs from 4 patients were analysed. All
CTVs were within the PTVs chosen for the PoD treatments.
The median reduction of CTV volume at the end of
treatments was 56%. The CTV reduced over the course of
treatment in all patients, and the largest extent of volume
reduction was found to be after the first 2 weeks of
treatment, with a median reduction of 37%.
The changes of dosimetric parameters on CTV and OARs
are summarised in the table below.
Dosimetric
parameters
Median % difference between the first
and last fraction of treatment
D98%CTV Increase by 1.15%
D50%CTV increase by 0.77%
V30Gy Bowel Increase by 77.66%
V40Gy Bowel Increase by 129.53%
V30Gy Bladder Decrease by V0.16%
V40Gy Bladder Increase by 5.50%
V30Gy Rectum Increase by 16.30%
V40Gy Rectum Increase by 51.08%
Given that PTVs remained unchanged, it follows logically
that the increased bowel dose can be directly attributed
to its anatomical displacement caused by a regressing
CTV.
Conclusion
This study has shown that consistent CTV coverage is
retained through the implementation of adaptive PoD,
though, the CTV volume reduces over the course of
treatment. As a result, the dose to bowel increases due to
the increased amount of bowel within the PTV. It is
suggested that proactive replanning of these patients
after the first 2 weeks of treatments might be beneficial,
in order to reduce bowel dose by taking account of tumour
regression.
EP-1849 Implementation and verification of DIBH
technique for treatment of left-sided breast cancer
patients
D. Dupla1, K. Konat1, M. Janiszewska2, A. Maciejczyk1, R.
Matkowski 3
1 Lower Silesian Oncology Center/Wrocław Medical
Uniwersity, Radiation Therapy/Oncology, Wrocław,
Poland
2 Lower Silesian Oncology Center, Medical Physics,
Wrocław, Poland
3 Wrocław Medical University, Oncology, Wrocław, Poland
Purpose or Objective
The aim of this study was to present specific way of
preparation, planning and realization of deep breath-hold
(DIBH) technique which is used for treatment of patients
with left-sided breast cancer.
Material and Methods
283 patients with left-sided breast cancer were irradiated
with DIBH technique controlled by Real-time Position
Management (RPM) system in Lower Silesian Oncology
Center (Wroclaw, Poland) from 2013 to April 2016.
Conventional fractionation of 50 Gy for breast with or
without regional lymph nodes, and 56,25/60,2 Gy for
simultaneous integrated boost in 25/28 fractions were
prescribed. 3D, 3D/Intensity Modulated Radiation
Therapy techniques were used. Correctness of realization
and reproducibility of irradiation was controlled by Image
Guided Radiation Therapy protocol. Before each of
fractions two orthogonal paired kV images on deep breath
hold to isocenter verification and correction was taken. In
addition two MV portal images using the treatment beam
to evaluate reproducibility of respiratory motion and to
control heart covering in tangential fields was taken. To
image analysis an Off-line Imaging Program in ARIA
Oncology Information System was used. Reproducibility of
movements during respiration under control of RPM
system was evaluated after set-up images matching to
spine and chest wall. Accuracy of patient positioning and
reproducibility of respiratory motion during radiation was
evaluated by analysis of tangential field imaging and
effectiveness of DIBH technique by presence of heart in
tangential fields.
Results
The average reproducibility of movements during
respiratory cycle controlled by RPM system was in a row -
0,07 (±0,2); 0,003 (±0,2); -0,009 (±0,02) cm in vertical,
longitudinal and lateral axis. Margin for reproducibility of
respiratory cycle was calculated according to van Herk
formula and equals: vertical:0,6; longitudinal:0,9 and
lateral:0,1 cm. Analysis of tangential field images has
shown high accuracy in patients positioning and
reproducibility of respiratory motion during radiation
therapy with mean systematic setup error Σ:0,037; 0,08;
0,034 cm in vertical, longitudinal and lateral axis. In spite
of high reproducibility of respiratory movements and
patients positioning part of the heart was included in some
tangential field images.
Conclusion
DIBH technique is an useful irradiation method to decrease
the rate of cardiac complications in left sided breast
cancer patients. Developing of detailed protocol of
imaging control for DIBH technique and its current analysis
is essential for adequate treatment realization. In spite of
good reproducibility of respiratory motion controlled by
RPM and elimination of set-up error by daily imaging
verification, in some cases irradiated field includes heart.
It may be caused by insufficient lung expansion caused by
wrong diaphragm movement, which is beyond RPM system
control. Proper instructions in thoracic and abdominal
breathing training are important issues in DIBH technique
implementation.
Electronic Poster: RTT track: Patient care, side effects
and communication
EP-1850 Effect on Smoking Behavior, Emotional
Distress and Quality of Life in Male H/N Cancer Survivors
H.Y. Kuan1, H.X. Zhao2, C.Y. Huang2, J.T.C. Chang1
1chang gung memorial hospital, Department of Radiation
Oncology, Taoyuan, Taiwan
2Chung Yuan Christian University, Department of
Psychology, Chungli, Taiwan
Purpose or Objective
To examine the moderation of search for meaning on the
relationship between presence of meaning, smoking
behavior, emotional distress, and quality of life among
male survivors with head and neck cancer.
Material and Methods
The head and neck cancer survivors completed the radical
cancer treatment longer than 6 months and with smoking
history were invited to the study. The participants were
interviewed with Substance Use Behavior Questionnaire,
Meaning in Life Questionnaire, Short Form Profile of the
Mood State, and Functional Assessment of Cancer Therapy
Scale-Head and Neck Version in addition to the basic
personal characteristic data. Multiple Regression Analysis
was used to examine the inter-action effects among
different interested outcome.