<abstract xmlns="http://www.w3.org/1999/xhtml">

<sec id="j_raon-2021-0045_s_006">
<h3>Background</h3>
<p>Non-coplanar volumetric modulated arc therapy (ncVMAT) is proposed to reduce toxicity in heart and lungs for locoregional radiotherapy of left-sided breast cancer, including internal mammary nodes (IMN).</p>
</sec>
<sec id="j_raon-2021-0045_s_007">
<h3>Patients and methods</h3>
<p>This retrospective study included 10 patients with left-sided breast cancer who underwent locoregional radiotherapy after breast-conserving surgery. For each patient, the ncVMAT plan was designed with four partial arcs comprising two coplanar arcs and two non-coplanar arcs, with a couch rotating to 90°. The prescribed dose was normalized to cover 95% of planning target volume (PTV), with 50 Gy delivered in 25 fractions. For each ncVMAT plan, dosimetric parameters were compared with the coplanar volumetric modulated arc therapy (coV-MAT) plan.</p>
</sec>
<sec id="j_raon-2021-0045_s_008">
<h3>Results</h3>
<p>T here were improvements in conformity index, homogeneity index and V<sub>55</sub> of total target volume (PTVall) comparing ncVMAT to coVMAT (<italic>p</italic> &lt; 0.001). Among the organs at risk, the average V<sub>30</sub>, V<sub>20</sub>, V<sub>10</sub>, V<sub>5</sub>, and mean dose (D<sub>mean</sub>) of the heart decreased significantly (<italic>p</italic> &lt; 0.001). Furthermore, ncVMAT significantly reduced the mean V<sub>20</sub>, V<sub>10</sub>, V<sub>5</sub>, and D<sub>mean</sub> of left lung and the mean V<sub>10</sub> and V<sub>5</sub> and D<sub>mean</sub> of contralateral lung (<italic>p</italic> &lt; 0.001). An improved sparing of the left anterior descending coronary artery and right breast were also observed with ncVMAT (<italic>p</italic> &lt; 0.001).</p>
</sec>
<sec id="j_raon-2021-0045_s_009">
<h3>Conclusions</h3>
<p>Compared to coVMAT, ncVMAT provides improved conformity and homogeneity of whole P TV, better dose sparing of the heart, bilateral lungs, left anterior descending coronary artery (LAD), and right breast for locoregional radiotherapy of left-sided breast cancer with IMN, potentially reducing the risk of normal tissue damage.</p>
</sec>
</abstract>

Background
Non-coplanar volumetric modulated arc therapy (ncVMAT) is proposed to reduce toxicity in heart and lungs for locoregional radiotherapy of left-sided breast cancer, including internal mammary nodes (IMN).


Patients and methods
This retrospective study included 10 patients with left-sided breast cancer who underwent locoregional radiotherapy after breast-conserving surgery. For each patient, the ncVMAT plan was designed with four partial arcs comprising two coplanar arcs and two non-coplanar arcs, with a couch rotating to 90°. The prescribed dose was normalized to cover 95% of planning target volume (PTV), with 50 Gy delivered in 25 fractions. For each ncVMAT plan, dosimetric parameters were compared with the coplanar volumetric modulated arc therapy (coV-MAT) plan.


Results
T here were improvements in conformity index, homogeneity index and V55 of total target volume (PTVall) comparing ncVMAT to coVMAT (p < 0.001). Among the organs at risk, the average V30, V20, V10, V5, and mean dose (Dmean) of the heart decreased significantly (p < 0.001). Furthermore, ncVMAT significantly reduced the mean V20, V10, V5, and Dmean of left lung and the mean V10 and V5 and Dmean of contralateral lung (p < 0.001). An improved sparing of the left anterior descending coronary artery and right breast were also observed with ncVMAT (p < 0.001).


Conclusions
Compared to coVMAT, ncVMAT provides improved conformity and homogeneity of whole P TV, better dose sparing of the heart, bilateral lungs, left anterior descending coronary artery (LAD), and right breast for locoregional radiotherapy of left-sided breast cancer with IMN, potentially reducing the risk of normal tissue damage.

Non-coplanar volumetric modulated arc therapy for locoregional radiotherapy of left-sided breast cancer including internal mammary nodes

Radiology and Oncology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Background
Non-coplanar volumetric modulated arc therapy (ncVMAT) is proposed to reduce toxicity in heart and lungs for locoregional radiotherapy of left-sided...

Non-coplanar volumetric modulated arc therapy for locoregional radiotherapy of left-sided breast cancer including internal mammary nodes

Article Category: Research Article

Published Online: Nov 19, 2021

Page range: 499 - 507

Received: Apr 27, 2021

Accepted: Sep 28, 2021

DOI: https://doi.org/10.2478/raon-2021-0045

© 2021 Yuan Xu, Pan Ma, Zhihui Hu, Yuan Tian, Kuo Men, Shulian Wang, Yingjie Xu, Jianrong Dai, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.