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S628
ESTRO 36 2017
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AAPM TG 72
(needle
method)
11
5
2 mm
1 mm
0.0 ÷ 20.0
mm (5.4
mm
on
the
average)
Conclusion
A new system for measuring the mammary gland thickness
prior to IOERT developed at Vicenza Hospital was
compared to a traditional needle method. The former
shows better reproducibility and accuracy, because it
reproduces the same target thickness as it exists after the
docking. Regarding both treatment decisions and
dosimetric accuracy, the found differences are critical
when the international recommendations are followed.
EP-1165 Short and long term safety of a post-
mastectomy conformal electron beam radiotherapy
(PMERT)
N. Grellier-Adedjouma
1
, M. Chevrier
2
, H. Xu
1
, N.
Fournier-Bidoz
1
, F. Campana
1
, F. Berger
2
, A. Fourquet
1
,
D. Peurien
1
, D. Lefeuvre
2
, Y.M. Kirova
1
1
Institut Curie, Radiation Oncology, Paris, France
2
Institut Curie, Statistics, Paris, France
Purpose or Objective
To evaluate short and long-term safety of a chest wall
irradiation after mastectomy with our previously
published PMERT technique, depending on patient
characteristics and treatments received.
Material and Methods
We included all women irradiated after mastectomy for a
non-metastatic breast cancer with PMERT between 2007
and 2011 in our Department of Radiation Oncology. Acute
and late toxicities (CTCAE v3.0) were evaluated with a
weekly clinical examination during irradiation and then
with monitoring consultations at least every 6 months. We
also conducted a dosimetric analysis of 100 consecutive
patients irradiated on the chest wall and lymph nodes (LN)
(50 right and 50 left), to assess the doses to organs at risk.
Results
Among the 796 women included, mean age was 53.2 years
(22.1-90.8), 47.6% of them had at least one cardiovascular
risk factor, regardless of age, 49% were post menopausal,
8.3% were obese (BMI ≥ 30) and 6.9% and 11.9% had cardiac
and
pulmonary
comorbidities
respectively.
Internal mammary chain (IMC) was irradiated in 85.6% of
cases, supra, infraclavicular LN and axilla in 88.3%, 77.9%
and 14.9% of cases. Mean chest wall dose was 49.4Gy (39-
56) over 40 days (30-119). Energies of 6 and/or 9 MeV were
used
in
84.7% of
cases.
The maximum acute skin toxicity was grade 1 in 58.5% of
patients, grade 2 in 35.9%, and grade 3 in 4.5% of them.
There was no grade 4 toxicity. Concomitant chemotherapy
was associated with an increased risk of grade 3 toxicity
(p <0.001).
With an median follow up of 64.1 months (5.6-101.5),
29.8% of patients had, temporarily or permanently,
hyperpigmentation, fibrosis or telangiectasia (grade 1:
23.6%, grade 2: 5.2%, grade 3: 1%), which tended to be
promoted by smoking (p = 0.06); 274 patients (34.4%)
underwent breast reconstruction, on average 19.7 months
after the end of irradiation (3.6-86.8), which was
considered as satisfactory or very satisfactory in 90% of
cases.
Lymphedema occurred in 17.1% of patients (minor: 14.4%,
severe: 2.7%), related to axillary radiotherapy (p<0.001)
and
obesity (p=0.017).
Long-term pulmonary toxicity reached 4% and was related
to the irradiated volume. Among the 95 patients with
pulmonary comorbidities, 9% experienced increased
respiratory symptoms after radiation therapy; it is not
possible to distinguish between radiation toxicity and
respiratory
disease evolution.
Late cardiac events were reported in 21 patients (2.7%),
of which 17 had received anthracyclines and 9
trastuzumab. Three patients developed ischemic heart
disease, within 5 to 7 years after radiotherapy; all of them
had received anthracyclines and were irradiated at the
left chest wall and LN, but also had many cardiovascular
risk
factors (2
to
4).
Mean heart doses were 4.35Gy (2.1-6.6) and 1.7Gy (0.5-
2.9) and mean ipsilateral lung doses were 13.9Gy (10.8-
17) and 12.4 (8.6-16.1), in case of left and right chest wall
and LN irradiation respectively.
Conclusion
This series shows that our PMERT technique is well
tolerated at short and long term.
EP-1166 Patterns of post-operative radiotherapy in
breast cancer patients after neoadjuvant chemotherapy
K.M. Lopes
1
, T.B. De Freitas
1
, H.A. Carvalho
1
, A.A.
Pereira
2
, S.B. Silva
2
, S.R. Stuart
1
, M.S. Mano
2
, J.R.
Filassi
3
, G.N. Marta
4,5
1
Faculdade de Medicina da Universidade de São Paulo,
Radiation Oncology, Sao Pailo, Brazil
2
Faculdade de Medicina da Universidade de São Paulo,
Clinical Oncology, Sao Pailo, Brazil
3
Faculdade de Medicina da Universidade de São Paulo,
Breast Division, Sao Pailo, Brazil
4
Hospital Sírio-Libanês, Radiation Oncology, São Paulo,
Brazil
5
Instituto do Câncer do Estado de São Paulo ICESP -
Faculdade de Medicina da Universidade de São Paulo,
Radiation Oncology, Sao Paulo, Brazil
Purpose or Objective
Neoadjuvant chemotherapy (NCT) has the same results as
adjuvant chemotherapy in regard to disease-free survival
and overall survival and may also allow breast conserving
surgery for patients with locally advanced breast cancer.
Indications for adjuvant radiotherapy (RT), as well as
treatment targets after NCT are not yet well established.
The purpose of this study is to evaluate locoregional RT
indications and treatment targets in breast cancer
patients submitted to NCT.
Material and Methods
Retrospective study of 523 patients treated between
March 2010 and April 2015 that were submitted to NCT and
received post-operative RT. Demographics, tumor and
treatment characteristics were evaluated. The variables
were submitted to descriptive and frequencies analysis.
Comparisons of categorical variables among groups were
made with the Chi-square test. Significance level was set
at 5% (p < 0.05).
Results
The mean age was 50 years (range 22 to 84 years). Most
patients had stage cT3 or cT4 disease (74.6%) and
clinically positive lymph node(s) (81.5%). Luminal “like”
tumors comprised 45% of the patients and 27.9% were
triple negative. Biopsy for suspected axillary lymph node
was performed in 49.5% (32.8% of these were positive).
Conservative surgery was performed in 23.1%. All patients
received breast or chest wall irradiation; 91.5%
supraclavicular fossa (SCF) and axillary levels 2 and 3
irradiation, 1.4% only SCF; 8.7% underwent additional
axillary level 1 irradiation and 8.8% also received internal
mammary chain RT; boost was delivered in 21.4% of the
patients. Conventional fractionation (25 x 200 cGy) was
used in 96.6%. Indication of SCF and levels 2 and 3 axillary
lymph nodes irradiation was significantly related to
younger age (≤ 60 years)(p = 0.03), stage cT3 or cT4
(p = 0.027) and clinically compromised lymph nodes at the
time of diagnosis (p = 0.0001). Internal mammary chain
irradiation was also correlated to clinically positive lymph
nodes (p = 0.01) and stage ypT3 or ypT4 (p = 0.028).
Conclusion