ESTRO 36 Abstract Book

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S335 ESTRO 36 2017
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alone, 17 patients with radiotherapy combined with
chemotherapy, 3 patients with chemotherapy alone and
one patient with anti-inflammation therapy. Survivals
were estimated using the Kaplan-Meier method.
Propensity Score Matching (PSM) was applied for 544
patients with ratio 1:2, and covariates included sex, B
symptoms, lactate dehydrogenase (LDH), ECOG
Performance Status, primary location, Ann Arbor stage
and primary tumor invasion. 116 patients with age≤60
were eventually matched by PSM.
Results
Median follow-up time was 39 months (range, 2-174
months) for 58 older patients and 30 months (range, 1-435
months) for 116 matched patients. Well-balanced pairs of
different covariates were established by PSM (p<0.05).
After matching, overall survival (OS), cancer-specific
survival (CSS), progressive free survival (PFS) and local-
reginal control (LRC) were no significant difference
between patients with age>60 and with age≤60. 5-year OS
were 61.4% and 68.9% (p=0.326), 5-year CSS were 69.1%
and 71.4% (p=0.902), 5-year PFS were 61.3% and 63.9%
(p=0.594), and 5-year LRC were 87.2% and 88.1%
(p=0.628), respectively.
Conclusion
Older patients with early stage UADT-NKTCL have good
prognosis after radiotherapy is the primary treatment.
Age>60 is not unfavorable prognostic factor for early stage
UADT-NKTCL. The patients with age>60 have similar
survivals with the patients with age≤60.
Poster: Clinical track: Breast
PO-0649 Locoregional Treatment of the Primary
Tumor Shows Survival Benefit in De Novo Stage IV
Breast Cancer
S.H. Choi1, W.J. Rhee1, J.W. Kim1, C.O. Suh1, K.C.
Keum1, Y.B. Kim1 , I.J. Lee1
1 Yonsei University, Radiation Oncology, SEOUL, Korea
Republic of
Purpose or Objective
Although systemic therapy is a mainstay of treatment for
metastatic breast cancer, the role of locoregional
treatment (LRT) of the primary tumor for an overall
survival advantage is still unclear. The aim of this study
was to assess the clinical outcomes of patients with de
novo stage IV breast cancer after undergoing LRT of the
primary site.
Material and Methods
From January 2006 to November 2013, a total of 245
patients diagnosed with de novo stage IV breast cancer at
Yonsei University Health System were included. Among
them, LRT of primary tumor (+ systemic therapy) was
performed in 86 patients (35%) (Surgery only : n = 28,
surgery + radiotherapy (RT) : n = 47, RT only : n = 11). The
remaining 155 patients (63%) received systemic therapies
(chemotherapy and/or hormone therapy), while 4 patients
(2%) received no treatment. For surgery type, 87% (n = 66)
received mastectomy, and 12% (n = 9) received breast-
conserving surgery (BCS). Local recurrence-free survival
(LRFS) and overall survival (OS) were investigated, and
propensity score matching method was used to balance
groups.
Results
The median follow-up duration was 40 months (Range, 13
days to 124 months). The 5-year LRFS and OS rates were
27% and 50%, respectively. Total of 188 patients (77%)
experienced recurrence, while local recurrence rate was
45% (LRT group 12% vs. no LRT group 47%, p <0.001) and
systemic recurrence rate was 95% (LRT group 69% vs. no
LRT group 76%, p=0.248). Advanced T stage (T4), liver or
brain metastasis, ≥5 metastatic sites, no hormone
therapy, and LRT(-) were considered significant adverse
factors for LRFS, while T4 stage, no hormone therapy, and
LRT(-) were considered significant for OS. LRT group
demonstrated favorable outcome (5-year LRFS: 55% and 5-
year OS: 71%), especially when surgery was performed.
Even after matching the baseline characteristics, survival
rates were still significantly higher in LRT group than no
LRT group (5-year LRFS 55% vs. 22%, p<0.001, 5-year OS
71% vs. 43%, p<0.001). Furthermore, LRT (especially
surgery) was an important good prognostic factor in
patients with <T4 stage tumors, no liver or brain
metastasis, and <5 metastatic sites in subgroup analysis.
For the type of surgery, BCS + RT was not inferior to other
LRTs, although more patients with early stage tumors or
≤2 sites, without lung/liver/distant lymph node
metastasis, were included. For the role of post-
mastectomy RT, treatment results were higher (5-year
LRFS 61% vs. 50%, OS 74% vs. 68%) with RT in selected T/N
stage (≥N2, ≥T3, or T2N1) of patients.
Conclusion
LRT including RT, together with systemic therapies, is an
important option in selected de novo stage IV breast
cancer patients, especially when the burden of the tumor
is low. Furthermore, BCS + RT would be a possible
substitute for mastectomy without compromising
oncologic outcome in early stage metastatic breast
cancer. Post-mastectomy RT should be re-evaluated in
light of the advances in systemic therapy, with improving
survival in stage IV disease.
PO-0650 Omitting radiotherapy in triple-negative
breast cancer leads to worse cancer-specific survival
I. Kindts1,2 , P. Buelens1,2, A. Laenen3, E. Van
Limbergen1,2, H. Janssen1,2, H. Wildiers 2,4, C. Weltens1,2
1University Hospitals Leuven, Department of Radiation
Oncology, Leuven, Belgium
2KU Leuven - University of Leuven, Department of
Oncology, Leuven, Belgium
3KU Leuven - University of Leuven, Leuven Biostatistics
and Statistical Bioinformatics Centre L-Biostat, Leuven,
Belgium
4University Hospitals Leuven, Department of General
Medical Oncology, Leuven, Belgium
Purpose or Objective
To examine the risk of locoregional recurrence (LRR) and
breast cancer-specific survival (BCSS) in triple-negative
breast cancer (TNBC) patients after breast conserving
therapy (BCT) or mastectomy (ME) with or without
radiotherapy (RT).
Material and Methods
We retrospectively identified cases with newly diagnosed
non-metastatic TNBC between 2000 and 2010 from a
prospectively collected single institution database.
Patients were excluded in case of no local surgery, no
adjuvant RT after breast conserving surgery or in case neo-
adjuvant chemotherapy was administered. LRR was
defined as local and or regional (axillar, parasternal or
supraclavicular region) recurrence. BCSS was defined as
death from breast cancer. Patients treated with BCT, ME
with RT (ME+RT) and ME only were compared with respect
to LRR and BCSS. Cox regression models were used to
analyze the association between prognostic factors and
outcome.
Results
439 patients fulfilled the inclusion criteria. Median follow-
up was 10.2 years. Patients in the BCT (n = 239), ME+RT (n
= 116) and ME only (n = 84) group differed with respect to
age, pT, pN, lymphovascular invasion, lymph node
dissection and the administration of chemotherapy.
Ten-year LRR rates were 7 %, 3 % and 8 % for the BCT,
ME+RT and ME only group, respectively. Patients with a
higher pN stage were at higher risk for LRR (HR 1.81, p
0.001). There was a trend towards more LRR in tumors
with lymphovascular invasion. LRR was compared for the
three groups in multivariable analysis with correction of