METHODS
In this study, 102 patients who underwent adjuvant RT for the treatment of breast cancer in our clinic
between November 2018 and December 2019 were included. A breast and/or chest wall, and/or lymph
node RT of 50 Gy in 25 fractions was planned for all patients, and an additional boost of 10 Gy in five
fractions was planned for patients requiring an RT boost. The treatment plans included 3DCRT, Field in
Field (FIF), IMRT and VMAT approaches.
RESULTS
In the group undergoing supraclavicular fossa RT, the mean V20Gy was found to be 24.8%, compared to
16% in the group not undergoing supraclavicular fossa RT (p<0.01). In the group undergoing mammaria
interna RT, the mean heart dose was 3.1 Gy, compared to 2.1 Gy in the group not undergoing mammaria
interna RT (p=0.04).
CONCLUSION
Respiratory motion control techniques can reduce uncertainties in the target related to respiratory motion.
The irradiated volume doses of the ipsilateral lung, heart reduce.
Keywords: Breast cancer; deep breath hold technique; radiotherapy
The deep inspiration breath-hold (DIBH) technique
has been developed to reduce doses of RT on the
lung and heart. There are different methods and systems
for the application of DIBH, including voluntary,
moderate or active breathing control [ABC]. Voluntary
DIBH (vDIBH) relies on patient coaching throughout
the respiratory cycle, whereas ABC DIBH makes use of
a spirometer-like device. Although both techniques are
effective, vDIBH is reported to be better tolerated.[
The vDIBH technique is based on observation of the
flattening of the diaphragm and the expansion of the
lungs during inspiration when the heart is moved away
from the chest wall. During both simulation and treatment,
the patient takes a deep breath and then holds it for
the duration of the treatment.[
The present study to retrospectively analyze the
doses of organs at risk, such as the lung and heart of patients
who underwent RT using the vDIBH technique,
and to compare them with the findings in the literature.
Simulation, Treatment Planning and Delivery
The breath-hold technique was described to all patients
by a training nurse before the simulation. All patients
were placed in the supine position on the breast board.
The surgical scar and palpable breast tissue were marked
with radiopaque wire. A Varian RPM (real-time position management) system (Varian Medical Systems,
Palo Alto, CA, USA) was used for the vDIBH technique.
The RPM box, placed on the patient's chest wall, detects
vertical displacements during the respiratory cycle, and
the patient is instructed to hold their breath during a
computer tomography (CT) (Aqullion LB TSX-201A,
Toshiba Medical Systems, Japan) scan. A specific cutoff
value for the upper and lower values of vertical displacement
of the patient's chest wall was determined. A
CT scan at 3 cm thickness was performed from the level
of the larynx to the center of the abdomen.
Target volume contouring and organs at risk
(OARs) (such as lungs, heart, esophagus, spinal canal
and contralateral breast) contouring were performed
in accordance with the Varian Eclipse planning system
(version 13.7 - Varian Medical Systems, Palo Alto,
USA) in accordance with the RTOG atlas.[
The Anisotropic Analytical Algorithm (AAA)
photon dose calculation algorithm was used for all
plans. The maximum dose rate was 400 MU/min for
the IMRT and 3DCRT plans, and 600 MU/min for the
VMAT plans. The dose calculation grid was selected
to be 0.25 cm. Treatment was delivered using a Varian
linear accelerator (Clinac IX, Varian Medical Systems,
Palo Alto, CA, USA).
The normality of the data was evaluated using a
Shapiro-Wilk or Kolmogorov-Smirnov test, depending
on the sample size. Since the data did not meet
the normality criteria, it was summarized as median,
minimum and maximum values. A Mann-Whitney
U test was used for between-group comparisons, and
a Kruskal-Wallis test was used for the comparison
of more than two groups. After the Kruskal-Wallis
test, pairwise comparisons were performed using the
Conover method. The significance level was set at 0.05
for all analyses.
A total dose of 50 Gy was administered to 57 patients,
and a boost treatment was administered to 46
patients as an additional 10 Gy in five fractions. The
3DCRT-FIF, IMRT and VMAT plans were delivered to
82, 3 and 17 patients, respectively. The mean CTV-50Gy
volume was found to be 859 cc. The treatment and CTV
parameter characteristics are specified in Table
The mean lung volume was 4373 cc. The administered
ipsilateral lung V20 and OAR doses are presented
in Table
The detailed comparison of the techniques and the
associated OAR doses is presented in Table
The doses absorbed by the lungs have been shown
to be less with DIBH when compared to free-breathing in many studies,[
Supraclavicular region RT increases the doses absorbed
by the lungs. In the present study, the lung
Dmean, V5, V10 and V20 values were statistically
higher in the patients who underwent additional supraclavicular
RT, and these values are consistent with the
literature.[
The risk of cardiovascular mortality has been shown
to increase after breast and/or chest wall RT.[
Regional nodal irradiation increases the doses absorbed
by the lungs and heart, with IMC irradiation
in particular increasing heart doses compared to breast
and chest wall irradiation alone.[
In line with our constitutional guidelines, the FIF
technique was first considered for all breast cancer
patients, while IMRT and VMAT techniques were
applied when the appropriate doses could not be
achieved by the FIF technique. Our institute criterion
for ipsilateral lung V20Gy is 35%. For the patients that
FIF technique could not provide this criterion VMAT
or IMRT was chosen for the treatment. The patients
who were treated with the IMRT and VMAT techniques
were generally patients who had additional regional
lymph node RT, particularly IMC-RT. Since the
IMRT technique was applied only to three patients,
and the VMAT technique was applied to 17 patients,
the comparison was not optimal, although contralateral
lung doses, contralateral breast doses, spinal canal
doses and esophagus doses were higher with these two
techniques compared to FIF.
The limitations of this study include: All patients
had RPM, and so there was no patient group without
RPM. Furthermore, the number of patients was not
homogeneous for different techniques.
Peer-review: Externally peer-reviewed.
Conflict of Interest: None.
Ethics Committee Approval: Yes.
Financial Support: None.
Authorship contributions: Concept - O.T., M.D.; Design - S.G.; Supervision - E.K.P., B.D.; H.G. - None; Materials - M.D.; Data collection and/or processing - O.T.; Data analysis and/or interpretation - F.A.E.; Literature search - M.D.; Writing - O.T., B.T.U.; Critical review - O.T.
