ESTRO 36 Abstract Book

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S638 ESTRO 36
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needed to validate these results with exclusion of possible
selection bias.
EP-1175 Impact of body-mass index on setup
displacement in patients with breast cancer
Y.C. Tsai1, C.Y. Chen2, J.T. Tsai1
1 Taipei Medical University-Shuang Ho Hospital, radiation
oncology, New Taipei City, Taiwan
2 Wan Fang Hospital- Taipei Medical University, Radiation
oncology, Taipei, Taiwan
Purpose or Objective
To determine the impact of body-mass indexfactors (BMIF)
on daily setup variations for patients with breast cancer
treated with adjuvant radiotherapy with daily image
guidance.before radiotherapy and changes
duringradiotherapy on the magnitude of setup
displacement in patients with breast cancer.
Material and Methods
The clinical data of 117 patients with breast cancer was
analyzed using the alignment data from daily on-lineon-
board imaging from image-guided radiotherapy between
2013 and 2015. All patients received cone beam computed
tomography(CBCT) at the first 5th fraction, then once per
week at least. BMFs included body weight, body height,
and thecircumference and bilateral thickness of the
neckThe shifts of each fraction were collected in superior-
inferior (SI), anterior-posterior (AP), and medial-lateral
(ML)directions respectively, and the absolute distant of
shifts was also calculated. The shifts of patients were
grouped by factors of BMI, body weight, height, age,
operation method and acute toxicities respectively. For
grouping of BMI,body weight and height, the median
values were used as cut off. The impact of factors as
assessed by compare the shifts using independent t-test
within each groups.
Results
Median BMI was 24.3, and median body weight was 59kg.
A higher body weight before radiotherapy correlated with
a greater shift in ML(p =0.0088 ), and SI(p = 0.0004)
direction. A larger BMI(≧24.3) was associated with a
greater shift in SI (p = 0.0005) direction. Comparsion of
patients undergoing breast-conserving surgery(BCS) and
modified radical mastectomy(MRM), BCS group was
associated with a larger shift in SI and ML(p=0.028 and
p=0.0051, respectively).
Conclusion
Larger body weight(≧ 59kg, larger BMI(≧ 24.3) and BCS may
be a significant risk factor for daily shifts.
EP-1176 Helical tomotherapy in chest wall/breast and
draining node irradiation after breast cancer surgery
V. Lancellotta1, M. Iacco1, S. Chierchini1, E. Perrucci1, I.
Palumbo1, L. Falcinelli1, S. Saccia 1, S. Nucciarelli1, A.
Milletti1 , C. Aristei1
1 Ospedale Santa Maria della Misericordia, Radiation
Oncology, Perugia, Italy
Purpose or Objective
Three dimensional conformal radiotherapy (3DCRT) to the
chest wall/breast and draining nodes has long
been standard treatment for patients at high-risk of
relapse after mastectomy or conserving surgery (BCS).
Given the complex target shape, other radiotherapy
techniques such as intensity modulated RT (IMRT),
volumetric modulated arc therapy (VMAT), helical (HT) or
direct (DT) tomotherapy were developed. The present
study evaluated the toxicity of HT for treating the chest
wall or breast plus level III and IV lymph nodes after
mastectomy or BCS.
Material and Methods
From January 2013 to August 2016, 43 consecutive
patients with breast cancer underwent helical
tomotherapy . Table 1 reports their demographics and
clinical details. Computed tomography (CT) scans without
contrast medium were acquired with patients supported
by breast board in the treatment position. CT data were
acquired with 2.5 mm slice thickness and were
transmitted to the Pinnacle 3 TPS V9.8. One radiation
oncologist contoured the clinical target volume (CTV) i.e.
chest wall or breast, level III and IV lymph nodes and
organs at risk. The chest wall was not expanded to obtain
the planning target volume (PTV); the breast and nodes
were expanded 0.5 cm in all directions to obtain the PTV
breast and PTV ln. Dose prescription was 50 Gy to the
PTVs in 25 fractions. In 7 patients treated with BCS a
simultaneous integrated boost (SIB) was delivered to the
tumoral bed. Dose constraints were defined by an internal
protocol following the QUANTEC directive and more
recent treatment plans were generated using
Tomotherapy HD System commercial planning software
(TomoTherapy Inc., Madison, WI). Daily set-up corrections
were performed for all patients.Toxicity was reported
following CTCAE 4.0. Statistical analysis: The Chi-square
and the Mann–Whitney's U-tests compared continuous
(age and body mass index) and categorical variables
(comorbidity, chemotherapy, hormonotherapy,
trastuzumab and chest wall/breast and lymph nodes
volumes).
Results
All patients completed treatment. HT provided good
target-coverage for the breast, chest wall and lymph
nodes, with respectively mean D90% 47.8Gy and 48.55Gy,
mean D95% 46.64Gy and 47.99Gy,mean D98% 45.20Gy and
47.3Gy, and mean V107% 0.65Gy and 0.315Gy. All
constraints for OARs were respected (i.e ipsilateral lung:
median V5: 70.93 Gy, V20: 24.2Gy and V30: 11.89Gy;
contralateral lung: V5: 24.17Gy and V15: 2.15Gy; heart:
Dmean 6.6 Gy). G1-G2 acute toxicity developed in 42
patients patients and G3 acute toxicity in only 1 (Table 2).
The only risk factor for desquamation and oedema
was chest wall/breast volume (p=0.003 and
p=0.011respectively). At a median follow-up of 12.5
months (range 2-29), all patients were alive and 41/43
(95.3%) patients were disease-free.
Conclusion
HT is associated with low acute toxicity and appears
suitable for treating the chest wall or breast plus level III
and IV draining nodes in patients with breast cancer.
EP-1177 Late radiation skin effects after breast
conserving surgery: possible predictive clinical factors.
A. Romano1, A. Rese1, E. Toska1, L. Faraci1, M. Conson1,
A. Farella1, R. Solla2, R. Liuzzi2, L. Cella 2, R. Pacelli1
1University of Napoli Federico II, Section of Radiation
Oncology, Napoli, Italy
2National Council of Research, Institute of Biostructure
and Bioimage, Napoli, Italy
Purpose or Objective
Previously we have shown that dose to surface and
psoriasis were predictive factors for radio-induced acute
skin toxicity in patients affected by breast cancer treated
with breast conserving therapy (BCT). In this study we
assessed in the same group of patients the late skin
toxicity, evaluating possible relation with acute skin
toxicity, dosimetric and clinical factors.
Material and Methods
One Hundred Forty patients treated with BCT between
2011 and 2012 in our department were considered for the
study. Median age was 57 year (range 32-85). All patients
were treated after surgery with 50 Gy to the whole breast
delivered with 25 daily fractions in 5 weeks. A boost dose
of 10 Gy in 5 days was delivered by electrons to the
tumoral bed. Late skin toxicity was assessed by physical
inspection during the oncological follow up of the patients