ESTRO 36 Abstract Book

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S91 ESTRO 36
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Proffered Papers: Breast
OC-0177 Brachytherapy for the Palliation of Dysphagia
Owing to Esophageal Cancer: A Systematic Review.
L. Fuccio 1, D. Mandolesi1, A. Farioli1, C. Hassan2, L.
Frazzoni1 , A. Guido3, F. Violante 1, C. Pierantoni1, A.
Galuppi3, F. Bazzoli1, A. Repici4, A. Morganti3
1 S.Orsola-Malpighi University Hospital, Department of
Medical and Surgical Sciences, Bologna, Italy
2 Nuovo Regina Margherita Hospital, Gastroenterology
Unit, Rome, Italy
3 S.Orsola-Malpighi University Hospital, Radiation
Oncology Unit, Bologna, Italy
4 Humanitas Research University Hospital, Endoscopy
Unit, Rozzano MI, Italy
Purpose or Objective
The management of dysphagia owing to eso phageal
cancer is challenging. Brachytherapy has been proposed as
an alternative option to stent placement. We performed a
systematic review to examine its efficacy and safety in the
resolution of dysphagia.
Material and Methods
Prospective studies recruiting at least 20 patients with
malignant dysphagia and published up to April 2016 were
eligible. The dysphagia-free survival (DFS) and adverse
event rates were pooled by means of a random effect
model.
Results
Six studies for a total of 9 treatment arms (623 patients)
were eligible for inclusion. After 1 month since treatment,
the DFS rate was 86.9% [95%CI: 76.0%–93.3%]; after 3
months, it was 67.2% [95%CI: 56.1%–76.7%]; after 6
months, it was 47.4% [95%CI: 38.5%–56.5%]; after 9
months, it was 37.6% [95%CI:30.0%–45.9%]; and, finally,
after 12 months, it was 29.4% [95%CI: 21.6%–38.7%]. The
heterogeneity between studies was high at 1-, 3- and 6-
month assessment; the values of I2 were 86.3%, 80.0% and
57.8%, respectively. The meta-regression analysis showed
total radiation dose and number of fractions as the only
positively influencing factors. Severe adverse event rate
was 22.6% (95%CI 19.4–26.3). The main reported adverse
events were brachytherapy-related stenosis (12.2%) and
fistula development (8.3%). Two cases (0.3%) of deaths
were reported due to esophageal perforation.
Conclusion
Brachytherapy is a highly effective and relatively safe
treatment option therefore its underuse is no longer
justified. Further studies should investigate the optimal
radiation dose and number of fractions able to achieve the
highest DFS rates.
OC-0178 Demonstration of Catheter Insertion Using
Electromagnetic Guidance in Breast Brachytherapy
H. Brastianos1, T. Vaughan 2, A. Lasso2, M. Westerland 1, J.
Gooding1, T. Ungi2 , G. Fichtinger2, C. Falkson1
1 Queen's University Cancer Research Institute, Radiation
Oncology, Kingston- Ontario, Canada
2 Queen's University, School of Computing, Kingston-
Ontario, Canada
Purpose or Objective
Accelerated partial breast irradiation using multi-catheter
interstitial brachytherapy may be used for early stage
breast cancers. To ensure ideal dosimetry over the tumor
bed, the catheters need to be placed in parallel with equal
spacing. The breast is a deformable organ; thus, placing
catheters in the correct position is challenging. To ensure
adequate spacing and position, we will apply real-time
electromagnetic guidance (EM) in combination with
ultrasound (US) to optimize the catheter insertions. This
study will discuss the use of electromagnetic tracking
catheter with ultrasound to insert catheters in phantoms.
Material and Methods
Anthropomorphic plastic phantoms were made with each
having a simulated tumor bed that can be visualized using
both ultrasound and CT. In the control, arm, the tumor is
identified using ultrasound and inserted under ultrasound
guidance.
A tissue-locking needle and US probe are equipped with a
real-time EM tracker. Under US guidance, the localization
needle is placed within the tumor bed, which provides a
rigid reference. The cavity is then contoured on US,
creating a model in a virtual view. An EM tracked needle
guide is pointed at the tumor bed and the catheter needle
is inserted through the guide into the tissue. Additional
parallel catheters are planned on the virtual view based
on the first insertion and implanted in the target. The
guidance software is built on the 3D Slicer
) and SlicerIGT open
source platforms.
In these experiments, a total of 10-15 catheters were
inserted in each of the six phantoms. The goal was to place
each catheter within the tumor bed. Three phantoms had
catheter needles inserted with ultrasound only, while the
other three had catheters inserted with combined EM
tracking and US guidance. All six insertions were
conducted by the same operator and the placement of the
catheters was determined with CT.
Results
Under US guidance only in the three phantoms, 17 out of
26 catheters passed through the tumor bed. The average
mean spacing was 0.86 cm +/- 0.33 cm. Under combined
EM tracking and US guidance, 35 out of 40 catheters
passed through the tumor bed. The average mean spacing
was 1.05 +/- 0.19 cm.
Conclusion
These phantom experiments verify that EM tracking can
be used to target catheter needles to the tumor bed.
Additional research is currently being performed to
translate this technique to patient trials.
OC-0179 Dosimetric impact of errors in HDR-iBT of the
breast using a catheter tracking method
M. Kellermeier 1, B. Hofmann1, V. Strnad 1, C. Bert1
1Universitätsklinikum Erlangen- Friedrich-Alexander-
Universität Erlangen-Nürnberg, Department of Radiation
Oncology, Erlangen, Germany
Purpose or Objective
Electromagnetic tracking (EMT) was used to measure the
implant geometry in fractioned HDR interstitial
brachytherapy (iBT) of the breast. Based on the tracking
data the dosimetric impact of common clinical errors, e.g.
as reported in the United States by the Nuclear Regulatory
Commission, were assessed using treatment planning
quality criteria (QC).
Material and Methods
For tracking of implant catheters, 28 patients were
accrued within an institutional review board-approved
study. The geometry of interstitial single-leader catheters
(median: 18 pcs) was tracked on the HDR treatment table
directly after each of the treatment fraction (up to nine
during five days). Tracking has been performed by manual
insertion of a small EMT sensor into each of the catheters.
The breathing motion was compensated by computing the
center of mass from three additional EMT sensors on the
breast. Taking the tracking-based catheter data, different
errors (swaps and shifts of catheters, changing the
tracking direction of catheters, i.e. tip-end swap) were
simulated.
For dose calculation, the dwell positions (DPs) were
determined along the catheter traces and the dwell times
were taken from the approved treatment plan. Common
contour-independent QC like the dose non-uniformity
ratio (DNR) were analyzed. For investigation of contour-
dependent QC, like the coverage index (CI) of the PTV, the
corresponding EMT-derived DPs were registered to the CT-