ESTRO 36 Abstract Book

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S636 ESTRO 36 2017
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assisted breast cup and imaged on a CT simulator with 1
mm slice thickness. Once the cup is placed, the negative
pressure is maintained until the treatment is
delivered. An inversely optimized treatment plan is
generated while the patient is transported and positioned
in the treatment room. Typical time between the imaging
session and completion of treatment is about 60 minutes.
Results
5 of the first 6 enrolled patients completed the
treatment. One patient’s lumpectomy cavity extended
outside the immobilized portion of the breast and
therefore did not meet the inclusion criteria for the study.
With the sources near its half-life, the treatment time
ranged from 17 minutes to 26 minutes. Dosimetrically, for
the 5 patients who completed their treatment, more than
95% of the prescription dose covered the clinical target
volume, and the maximum dose (D2% ) varied from 13% to
20% of the prescription dose (see figure of sample dose
distribution). With a median follow-up of 3 months, none
of the patients developed treatment related toxicity.
Conclusion
Initial results indicate that the GammaPod system can
deliver a focal dose of radiation to the breast safely. The
vacuum-assisted breast cups were able to maintain the
immobilization between imaging and treatment. With
dynamic dose painting, the dose uniformity rivals that of
external beam partial breast irradiation, but with more
rapid dose fall-off outside the target, leading to
substantially reduced radiation dose to the normal
breast. The ability of delivering a focal dose of radiation
opens the opportunity for single pre-operative irradiation
as an alternative to intra-operative irradiation and pre-
operative radioablation.
EP-1184 HDR boost decreases the risk of breast failure
in invasive breast ca. with close or involved margins
J.L. Guinot1, M.I. Tortajada1, M.A. Santos1, F. Romero1,
A. Moreno 2, V. Campo3 , L. Oliver3, P. Santamaria1, J.
Fernandez4, L. Arribas1
1 Fundación Instituto Valenciano de Oncologia,
Department of Radiation Oncology, Valencia, Spain
2 Fundación Instituto Valenciano de Oncologia,
Department of Radiation Oncology, Alcoy Alicante, Spain
3 Fundación Instituto Valenciano de Oncologia,
Department of Radiation Physics, Valencia, Spain
4 Fundación Instituto Valenciano de Oncologia,
Department of Radiation Oncology, Cuenca, Spain
Purpose or Objective
The risk of breast failure after breast-conserving
treatment is two-fold higher in invasive carcinoma with
positive surgical margins than in free margins, (between
12 and 34% at ten years) (1). A new resection is
recommended, with risk of fair cosmetic result, or
mastectomy. With close margin total dose should be
higher to avoid local recurrence. Twenty years ago, we
started with a high dose rate (HDR) boost after whole
breast irradiation in cases with close or positive margin.
We review the long-term outcome in these high risk cases
Material and Methods
Between 12.1996 and 12.2011, 248 patients were
included, with a median age of 55 (22-90). Mean FU 127
months. By T stage 179 T1, 62 T2 and 6 T3. By margin
status, 120 was positive, 76 close until 2mm, 52 close
>2mm and <5mm. All of them were treated with whole
breast irradiation (WBI) 50Gy plus HDR boost with 3
fractions of 4.4Gy to 85% isodose in two days, with rigid
needles. The contour of CTV was decided by clinical
assessment, no CT planning was used. Chemotherapy was
used in 52%, and hormonal treatment in 76%. Survival was
calculated by Kaplan Meyer method.
Results
In the whole population, actuarial breast failure at 10 and
15 years was 6.5% and 11.6%. With positive margin: 6.8%
and 14.8%, with close margin ≤2mm: 9.8% and 9.8%, with
margin >2mm <5mm, 2% and 2%. By age, in 90 patients
aged 50 or younger, was 11.9% and 17.8%, between 51-70,
3.8% and 8.2%, and no failures over 70. In young women
under 50 with positive margin, breast recurrence was
13.1% and 24% at 10 and 15 years. By T stage, no
differences between T1 and T2, no failures in T3. No
differences if margin was due to invasive carcinoma or
DCIS, in G3, or depending on hormonal receptors. Fibrosis
or induration were registered in 26.7%, breast edema
6.5%, volume reduction 6.5%, telangiectasia 3.4%,
hyperpigmentation 2.1%. Cosmetic outcome was
excellent/good in 85.8%.
Conclusion
Long-term breast control of patients with positive or close
surgical margin using WBI plus a HDR boost is similar to
that achieved with free margins in the EORTC 22881-10882
trial, in all groups of age, but in young women with
positive margin where a new resection is recommended.
This approach is useful to avoid a second intervention, in
women over 50 with positive surgical margin, or with close
margins in all ages.
(1) Guinot JL, et al. Breast-conservative surgery with close
or positive margins: can the breast be preserved with high-
dose-rate brachytherapy boost? Int J Radiat Oncol Biol
Phys 2007; 68:1381-87
EP-1185 Post-operative Irradiation after Nipple-
Sparing or Skin-Sparing Mastectomy: An International
Survey
G.N. Marta1,2, P. Poortmans3, R.A. Audisio4, R. Freitas
Junior5, A.C. De Barros6, J.R. Filassi7, S.M. DeSnyder8, S.
Meterissian9, T.A. Buchholz 10, T. Hijal11
1Hospital Sírio-Libanês, Radiation Oncology, São Paulo,
Brazil
2Instituto do Câncer do Estado de São Paulo ICESP -
Faculdade de Medicina da Universidade de São Paulo,
Radiation Oncology, Sao Paulo, Brazil
3Radboud university medical center, Radiation Oncology,
Nijmegen, The Netherlands
4University of Liverpool, Surgical Oncology, Liverpool,
United Kingdom
5Universidade Federal de Goias, Surgery, Goias, Brazil
6Hospital Sírio-Libanês, Surgery, Sao Paulo, Brazil
7Faculdade de Medicina da Universidade de São Paulo
FMUSP, Breast Surgery Division, Sao Paulo, Brazil
8The University of Texas MD Anderson Cancer Center,
Surgical Oncology, Houston, USA
9McGill University Health Centre, Surgery, Montreal,
Canada
10The University of Texas MD Anderson Cancer Center,
Radiation Oncology, Houston, USA
11McGill University Health Centre, Radiation Oncology,
Montreal, Canada
Purpose or Objective
Skin sparing mastectomy (SSM) and nipple-sparing
mastectomy (NSM) have entered routine surgical practice
for breast cancer, though their oncologic safety has not
been established in randomized controlled trials. The aim
of this study was to evaluate breast surgeons’ opinions
concerning the indications of post-operative radiation
after SSM and NSM.
Material and Methods
Breast surgeons from North America, South America and
Europe were invited to contribute in this study. A 22-
question survey was mailed to participating breast
surgeons to evaluate their opinions. the indications of
post-operative radiation after SSM and NSM.
Results
A total of 252 breast surgeons answered the questionnaire.
Most of them had at least 10 years of post-residency
practice. The majority of breast surgeons affirmed that
post-operative radiation should be performed in early-
stage (stages I and II) breast cancer for patients
who present with risk factors for relapse after SSM and