ESTRO 36 Abstract Book

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S117 ESTRO 36 2017
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Purpose or Objective
It was proposed that in some patients with early breast
cancer (BC) breast-conserving surgery with subsequent
irradiation of remaining breast tissue and sentinel lymph
nodes (SLN) should provide sustained control over BC and
achieving high rates of disease-free survival.
Purpose: to evaluate diagnostic accuracy of SPECT-CT
with 99mTc-MIBI in predicting non-SLN invasion by BC. To
determine efficacy of SPECT-CT (with 99mTc-
radiocolloids) visualization of axillary SLN for radiotherapy
planning. To determine treatment algorithms based on
SPECT-CT examinations with 99mTc-MIBI and 99mTc-
radiocolloids in patients with early BC.
Material and Methods
Accuracy of SPECT-CT in diagnosis of axillary non-SLN
invasion (metastases in 2 and more lymph nodes) was
prospectively evaluated in 186 primary women with cT1-
3NxM0 BC. Diagnostic results were evaluated by
histological examination of removed axillary LN: in 84
cases – by sentinel LN biopsy, in 102 – by standard axillary
LN dissection.
In 153 BC patients we determined topography of axillary
SLN and their relation within standard tangential
radiotherapy fields used for breast irradiation after
conservative surgery. Distribution of axillary SLN was
allocated to following subregions: central(C), anterior
pectoral(AP), sub-(SP) intrapectoral (IP), lateral (L),
subscapular (SSc), pectoral nodes lying close to thorax
wall (Th).
Finally, on routine 3D treatment plans of 10 consecutive
patients we examined radiation doses absorbed by SLN
localized in various axillary subregions and analyzed dose
distribution with different fields set up.
Results
In the first study histological sings of axillary lymph nodes
involvement were detected in 66 of 186 evaluated
patients, 43 of them had invasion of non-SLN. Sensitivity
of hybrid SPECT-CT imaging with 99mTc-MIBI in diagnosis
of axillary non-SLN invasion was 93%. This high sensitivity
help us to determine women that can be treated by
irradiation of SLN without axillary surgery.
In 153 women of the second group we used SPECT-CT with
radiocolloids to determine topography of SLN. We
mentioned following distribution of axillary SLN: C-
64(50.5%), AP–34(26.8%), Th–19(14.9%), L or SSc–10(7.8%).
In 17(13.4%) cases SLN were localized both on the I and
II(IP, SP) levels.
Evaluation of 3D treatment plans demonstrated that
standard tangential radiation fields does not cover SLN in
80% cases. In 20% they encompass C, AP, IP, SP nodes.
Modification of tangential fields permit effective
irradiation of C, AP, IP, SP, L, SSc nodes in all cases. Th
LN can be covered only by IMRT technique.
Conclusion
SPECT-CT with 99mTc-MIBI can effectively diagnose non-
SLN invasion by BC and subsequent SPECT-CT with
radiocolloids permit accurate planning and irradiation of
SLN by extended tangential radiation fields. This strategy
can be considered as alternative to treatment with
surgical axillary staging.
PV-0235 Is there a subset who benefits from PMRT in
node-negative breast cancer patients?
H.J. PARK1, K. Shin2, J. Kim 3, S. Ahn 4, S. Kim 4, Y. Kim5,
W. Park6, Y. Kim7, S. Shin8, J. Kim 9, S. LEE10, K. Kim11 , K.
Park12, B. Jeong 13
1 Hanyang University Hospital, Department of Radiation
Oncology, Seongdong-gu- Seoul, Korea Republic of
2 Seoul National University College of Medicine,
Department of Radiation Oncology, Seoul, Korea
Republic of
3 Seoul National University Hospital, Department of
Radiation Oncology, Seoul, Korea Republic of
4 Asan Medical Center- University of Ulsan College of
Medicine, Department of Radiation Oncology, Seoul,
Korea Republic of
5Yonsei Cancer Center- Yonsei University College of
Medicine, Department of Radiation Oncology, Seoul,
Korea Republic of
6Samsung Medical Center- Sungkyunkwan University
School of Medicine, Department of Radiation Oncology,
Seoul, Korea Republic of
7Proton Therapy Center- National Cancer Center,
Department of Radiation Oncology, Goyang, Korea
Republic of
8Bundang CHA Hospital- School of Medicine- CHA
University, Department of Radiation Oncology,
Seongnam, Korea Republic of
9Dongsan Medical Center- Keimyung University School of
Medicine, Department of Radiation Oncology, Daegu,
Korea Republic of
10Chonbuk National University Hospital, Department of
Radiation Oncology, Jeonju, Korea Republic of
11Ewha Womans University School of Medicine,
Department of Radiation Oncology, Seoul, Korea
Republic of
12Ewha Womans University Mokdong Hospital,
Department of Radiation Oncology, Seoul, Korea
Republic of
13Gyeongsang National University Hospital- Gyeongsang
National University School of medicine, Department of
Radiation Oncology, Jinju, Korea Republic of
Purpose or Objective
This study was performed to identify a subset of patients
who may benefit from post-mastectomy radiotherapy
(PMRT) among node-negative patients.
Material and Methods
We retrospectively reviewed 1,828 patients with pT1-2N0
breast cancer, treated with mastectomy without PMRT
from 2005 to 2010 at 10 institutions. Univariate and
multivariate analyses for locoregional recurrence (LRR)
and any first recurrence (AFR) were performed according
to clinicopathologic factors and biologic subtypes.
Results
During a median follow-up period of 5.9 years (range: 0.7–
10.4 years), 98 patients developed AFR (39 cases of
isolated LRR, 13 of LRR with synchronous distant
metastasis, and 46 of isolated distant metastasis), and 52
patients developed LRR (31 cases of local recurrence, 28
of regional recurrence, and 7 of local and regional
recurrence). The 10-year LRR and AFR rates were 3.8% and
7.9%, respectively. Multivariate analysis revealed that an
age of ≤ 40 years (hazard ratio [HR], 3.3; p < 0.001) and
stage T2 cancer (HR, 1.3; p = 0.013) were independent risk
factors for LRR. The 10-year LRR rates were 2.5% with no
risk factors, 4.5% with one risk factor, and 12.4% with two
risk factors. Multivariate analysis for AFR revealed that an
age of ≤ 40 years (HR, 2.6; p < 0.001), stage T2 cancer
(HR, 1.3; p < 0.001), and the triple-negative biological
subtype (HR, 1.6; p = 0.045) were independent risk factors
for AFR. The 10-year AFR rates were 3.9% with no risk
factors, 10.6% with one risk factor, and 18.1% with two to
three risk factors.
Conclusion
Mastectomy without PMRT is a sufficient local treatment
for pT1-2N0M0 breast cancer. Nevertheless, PMRT might
be considered for patients with two or three risk factors,
among those of young age, with T2 tumors, and with the
triple-negative biological subtype based on LRR and AFR.
PV-0236 Impact of radiation therapy delay in patients
underwent neoadjuvant chemotherapy and breast
surgery
S. Silva1, A. Pereira1, M. Kennya2, M. Gustavo2, M. Mano1
1Instituto do Cancer do Estado de São Paulo Universidade
de São Paulo-, Clinical Oncology, São Paulo, Brazil
2Instituto do Cancer do Estado de São Paulo Universidade
de São Paulo-, Radiotherapy, Sao Paulo, Brazil