ESTRO 36 Abstract Book

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S982 ESTRO 36
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EP-1788 HDR vs LDR Vaginal brachytherapy: a
comparison in terms of outcomes and toxicity
R. Autorino1, D. Smaniotto1, M. Campitelli1, L.
Tagliaferri1, A. Nardangeli1, G. Mattiucci1, A. Martino1, N.
Di Napoli 1, G. Ferrandina 2, M. Gambacorta1, V. Valentini1
1 Polyclinic University A. Gemelli- Catholic University,
Institute of Radiotherapy, Rome, Italy
2 Polyclinic University A. Gemelli- Catholic University,
Institute of Oncological Gynecology, Rome, Italy
Purpose or Objective
To compare the outcomes in terms of survival and toxicity
for endometrial carcinoma patients treated with either
HDR or LDR vaginal brachytherapy (VBT) after external
beam radiotherapy
Material and Methods
From January 2000 to December 2014, patients with
endometrial cancer after radical hysterectomy +/- pelvic
and/or lombo-aortic lymphadenectomy were treated with
adjuvant radiotherapy (45 Gy, 1.8 Gy/day on the whole
pelvis) and subsequential VBT boost (HDR dose was 7 Gy in
one fraction prescribed to 0.5 cm from the surface of the
applicator; LDR dose was 25 Gy to the vaginal mucosa).
The outcomes of patients were evaluated in terms of local
control (LC), overall survival (OS) and toxicity (according
to CTCAE v 4.0).
Results
We retrospectively analyzed 200 patients treated with
external beam radiation therapy followed by a HDR VBT
boost in 78 patients and LDR VBT boost in 122 patients.
Patients characteristics are summarized in Table 1.With a
median follow-up of 25 months (range 1-163), 5-ys overall
suvival (OS) was 98% vs 97% in LDR and HDR group
respectively (p=0.37) and 5-ys local control (LC) was 93%,
similar in the two groups (p=0.81).At multivariate
analyses, any factors (age, stage, grading) seems to have
impact on OS (p=0.37) and LC (p=0.81). Patients treated
with LDR VBT after external beam radiotherapy had an
higher gastrointestinal acute toxicty; probably, this is due
to development of radiation tecnique over the years of
this study. No differences was found in terms of acute
genitourinary and hematological toxicity. Late toxicity
such as vaginal stenosis was registered during regular
follow-up visit by clinical evaluation. We didn’t find
statistically significant differences between the two
modalities (p=0.67).
Conclusion
With the limits of a restrospective review, there were no
differences in survival and late toxicity outcomes for
patients receiving LDR or HDR brachytherapy. HDR is safe
technique in comparison to LDR modality. A larger
database analysis will confirm outcomes and toxicity of
HDR VBT in postoperative endometrial cancer.
EP-1789 Comparison between MRI based 3D IGABT
planning versus standardised BT planning of cervical
cancer
M. Hedetoft1
1 Skåne University Hospital, Department of Radiation
Physics, Lund, Sweden
Purpose or Objective
The aim of this study was to investigate if the introduction
of MRI based Image Guided Adapted Brachy Therapy
(IGABT) treatment planning of cervical cancer in our
hospital, has improved the target coverage and reduced
the dose to Organs at Risk (OAR) in comparison to standard
treatment planning with point A dose prescription.
Material and Methods
In February 2014 the first brachytherapy treatment of a
cervical cancer patient planned with MRI based 3D IGABT
technique, was undertaken in Lund. Until the end of
August 2016, 38 patients have been treated with this
technique resulting in 142 fractions, all of them included
in this study. The tumour stages of the patients included
were IB1 (n=5), IB2 (n=5), IIA (n=7), IIB (n=16), IIIB (n=5).
Each patient received external beam radiation therapy
and 2 or 4 brachytherapy fractions depending on the
tumour stage. For brachytherapy treatments the
interstitial titanium ring and tandem applicator (Varian
Medical Systems) were used. To be able to choose if an
interstitial treatment would improve the tumour coverage
a pre-plan was always done. 21 patients were selected for
intracavitary/interstitial implant and 17 for intracavitary
implant only.
Based on the MRI target volumes, GTV, HR-CTV, IR-CTV
and OARs (bladder, rectum, sigmoid and bowel) were
contoured according to GEC-ESTRO recommendations. The
dwell times were optimised for each fraction, 6.5 Gy/fr
and the plans were evaluated according to DVH criteria
from the EMBRACE II study.
For all fractions the optimised 3D plan was compared to a
2D plan with standardised dwell times, the same pre-plan
that was used for patient treatments before starting with
the IGABT. The standard plan was based on the same MR
images, target volumes and OARs as in the optimised plan.
The DVH criteria used for evaluation were EQD2 D90 for HR-
CTV, D2cm³ for rectum, D2cm³ for bladder, D2cm³ for sigmoid
and D2cm³ for bowel.
Results
All HR-CTVs with volumes <40cm 3 were covered with
>90Gy EQD2 for the standard as well as the optimised
plans. For 10 patients the standard plan coverage even
exceeded 100Gy EQD2. In the optimised plans the dose to
OAR could be decreased for 17 patients while still
maintaining the target coverage .
For larger tumours, HR-CTV >40cm3, the dose coverage
decreased with standard plans while the optimised plans
maintained excellent dose coverage for all plans. With
optimisation a good target coverage was obtained at the
cost of an increased but acceptable OAR dose.
Conclusion
In comparison to standardised plans, MRI-based 3D IGABT
planning substantially improved target coverage for larger
tumours without violating the OAR dose. For smaller
tumours the OAR dose was reduced without compromising
the target coverage.
Electronic Poster: Brachytherapy: Anorectal
EP-1790 A balloon applicator with adjustable
catheters for image-guided endoluminal rectal
brachytherapy
M. Heilmann 1, D. Berger1, R. Schmid 1, J. Bör 1, B.
Wisgrill1, R. Pötter1, C. Kirisits1, M.P. Schmid1
1Medizinische Universität Wien Medical University of
Vienna, Universitätsklinik für Strahlentherapie, Vienna,
Austria
Purpose or Objective
To investigate the dosimetric results and first clinical
experience with an in-house made balloon-based
applicator for endoluminal brachytherapy for patients
with locally advanced rectal cancer not undergoing
surgery.
Material and Methods
The applicator consists of an inflatable rectal balloon with
six attached foley catheters used as guidance for
brachytherapy plastic needles. The construction of the
applicator and the dosimetric profile in terms of
representative dose points in 0, 2, 5, 10 mm ipsilaterally
and in 0mm contralaterally are described. Feasibility and
treatment response in three patients are reported.