ESTRO 36 Abstract Book

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S631 ESTRO 36 2017
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Conclusion
This study demonstrated the feasibility of capturing local
temperature elevation over the course of adjuvant
radiotherapy for breast cancer. Maximal and average local
temperature increased for all patients, confirming the
intensity of inflammatory phenomena linked to
irradiation. Patients suffering from high-grade radiation-
induced dermatitis radiated noticeably more heat.
Furthermore, they started doing so before the occurrence
of clinical signs of dermatitis. As such, thermography
showed promising results as a predictive tool for the
occurrence of acute skin toxicity.
EP-1172 Post-mastectomy radiotherapy with patient-
tailored bolus using 3D printing for left breast cancer
K. Yang1, Y. Chung1 , W. Park1, S.G. Ju1, S.J. Huh1, D.H.
Choi1, H. Cha1, J.Y. Park1, C.H. Na1
1 Samsung Medical Center, Radiation Oncology, seoul,
Korea Republic of
Purpose or Objective
Radiation exposure to the heart during radiotherapy for
left breast cancer patients has a chance to increase the
risk of cardiovascular disease. Also, radiation pneumonitis
and decreased lung function associated with thoracic
radiotherapy have been reported. The purpose of this
study is to reduce heart and ipsilateral lung doses using an
optimized chest wall electron beam therapy with patient-
tailored bolus (PTB) using 3D printing technology for left
breast cancer patients after mastectomy.
Material and Methods
Five patients with left breast cancer underwent computed
tomography (CT) simulation for irradiation of left chest
wall and supraclavicular fossa after mastectomy. We
designed a virtual bolus on the chest wall to compensate
the surface irregularities on CT images and developed a
plan for chest wall electron beam therapy. Also, a rival
plan for conventional tangential technique was done on
the same CT. For both plans, supraclavicular field was
planned using photon beam. For planning, virtual bolus
was overridden by a density of material which would be
used to make PTB with 3D printer. Dosimetric comparisons
for target and organs at risk such as heart and ipsilateral
lung were performed between the 3D PTB applied electron
beam plan and tangential plan. Wilcoxon signed-rank test
was used for statistical analysis.
Results
For cardiac dose, PTB applied electron plan showed lower
Dmean, Dmax. V5Gy and V30Gy than tangential plan (p=0.080,
0.043, 0.686 and 0.068, respectively). For ipsilateral lung,
Dmean and V20Gy of electron plan were lower (p=0.080 and
0.043, respectively) than those of tangential plan, while
Dmax between two plans were less different. For target
coverage, all of Dmean, Dmax, D min, conformity index (CI) and
homogeneity index (HI) of electron plan were higher than
those of tangential plan (p=0.043, 0.043, 0.043, 0.225,
0.034, respectively).
Conclusion
Chest wall electron beam therapy with PTB reduced high
dose exposed cardiac and lung volume with clinically
acceptable target coverage compared with tangential
technique. Postmastectomy radiotherapy using PTB might
be effective for left breast cancer patients to reduce risk
of cardiac disease and lung morbidity.
EP-1173 Understanding variations in the use of
hypofractionated radiotherapy for breast cáncer
J.M. Borras1, J. Prades1, M. Algara2, J.A. Espinàs1, B.
Farrús3, M. Arenas4, V. Reyes5, V. Garcia-Reglero6, M.J.
Cambra7, E. Rubio Calatayud8, L. Anglada9, A. Eraso10, A.
Pedro11, M.J. Fuentes-Raspall12 , V. Tuset13
1Institut Català d'Oncologia, Cancer plan, L'Hospitalet de
Llobregat, Spain
2Hospital de l'Esperança- Parc de Salut Mar,
Radiotherapy, Barcelona, Spain
3Hospital Universitari Clinic de Barcelona, Radiotherapy,
Barcelona, Spain
4Hospital Universitari Sant Joan de Reus, Radiotherapy,
Reus, Spain
5Hospital Universitari Vall d´Hebron, Radiotherapy,
Barcelona, Spain
6Hospital Universitari Arnau de Vilanova, Radiotherpy,
Lleida, Spain
7Hospital General de Catalunya- Institut Oncològic del
Vallès, Radiotherpay, Barcelona, Spain
8Consorci Sanitari de Terrassa, Radiotherapy, Terrassa,
Spain
9Institut Català d'Oncologia- Girona, Radiotherapy,
Girona, Spain
10Institut Català d'Oncologia, Radiotherapy, L'Hospitalet
de Llobregat, Spain
11Hospital Clínica Plató, Radiotherapy, Barcelona, Spain
12Hospital de la Santa Creu i Sant Pau, Radiotherapy,
Barcelona, Spain
13Hospital Universitari Germans Trias i Pujol,
Radiotheraoy, Badalona, Spain
Purpose or Objective
Radiation oncology guidelines favour hypofractionated
whole-breast radiotherapy (HWBRT) over more
conventional schemes in the conservative treatment of
breast cancer, but its adoption still varies in clinical
practice. This study assessed the patterns of HWBRT use
and adoption in Catalonia (Spain).
Material and Methods
We used a mixed-methods approach based on an
explanatory sequential design, first collecting and
analysing quantitative data on HWBRT use (> 2.5 Gy per
fraction) in 11 public radiotherapy centres (2005–2015)
and then performing 25 semi-structured interviews with
all department heads and reference radiation
oncologist/s.
Results
Of the 34,859 patients fulfilling the study criteria over the
study period, just 12% were hypofractionated, reaching a
rate of 29% in 2015 (p<0.001). Our analysis showed a
narrowing age gap between patients receiving
conventional fractionation and hypofractionation in
centres leading adoption. However, there were important
differences in clinicians’ interpretation of evidence and
selection of patients for specific indications, both within
and between departments. Clinical management of
radiotherapy departments played a major role.
Conclusion
In tackling inequitable access to HWBRT, a rational,
evidence-based approach should ideally converge with
professional perspectives, the factors influencing the
interpretation of the evidence, and the organisational
context, including existing dissemination channels.
EP-1174 impact of radiotherapy to posterior
supraclavicular and posterior triangle area in breast
cancer