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

<italic>Objective:</italic> We compared mono-isocenter and dual-isocenter plans in synchronous bilateral breast cancer (SBBC), which is defined as tumours occurring simultaneously in both breasts, and evaluated the effects of these differences in plans on organs-at-risk (OARs).
<italic>Materials and methods:</italic> We evaluated 10 women with early stage, nod negative (Tis-2N0M0) SBBC. The treatment dose was determined to be 50 Gy. We used mean dose and VXGy to evaluate the OARs. To evaluate the effectiveness of treatment plans, Homogeneity index (HI), conformity index (CI) and sigma index (SI) and monitor units (MU) of monoisocenter (MIT) and dual-isocenter (DIT) plans were compared. During bilateral breast planning, for the single-centre plan, the isocenter was placed at the center of both breasts at a depth of 3-4 cm. For the two-center plan, dual-isocenters were placed on the right and left breasts.
<italic>Results:</italic> No significant difference between the techniques in terms of the scope of the target volume was observed. Statistically significant results were not achieved in MIT and DIT plans for OARs. Upon comparing MIT and DIT, the right-side monitor unit (MU) value in DIT (p = 0.011) was statistically significantly lower than that in MIT. Upon comparing right-left side MIT and DIT, the MU value (p = 0.028) was significantly lower in DIT than MIT.
<italic>Conclusion:</italic> SBBC irradiation is more complex than unilateral breast radiotherapy. No significant difference between both techniques and OARs was observed. However, we recommend MIT as a priority technique due to the ability to protect OARs, ease of administration during treatment, and the fact that the patient stays in the treatment unit for a shorter period of time.
</abstract>

Objective: We compared mono-isocenter and dual-isocenter plans in synchronous bilateral breast cancer (SBBC), which is defined as tumours occurring simultaneously in both breasts, and evaluated the effects of these differences in plans on organs-at-risk (OARs).
Materials and methods: We evaluated 10 women with early stage, nod negative (Tis-2N0M0) SBBC. The treatment dose was determined to be 50 Gy. We used mean dose and VXGy to evaluate the OARs. To evaluate the effectiveness of treatment plans, Homogeneity index (HI), conformity index (CI) and sigma index (SI) and monitor units (MU) of monoisocenter (MIT) and dual-isocenter (DIT) plans were compared. During bilateral breast planning, for the single-centre plan, the isocenter was placed at the center of both breasts at a depth of 3-4 cm. For the two-center plan, dual-isocenters were placed on the right and left breasts.
Results: No significant difference between the techniques in terms of the scope of the target volume was observed. Statistically significant results were not achieved in MIT and DIT plans for OARs. Upon comparing MIT and DIT, the right-side monitor unit (MU) value in DIT (p = 0.011) was statistically significantly lower than that in MIT. Upon comparing right-left side MIT and DIT, the MU value (p = 0.028) was significantly lower in DIT than MIT.
Conclusion: SBBC irradiation is more complex than unilateral breast radiotherapy. No significant difference between both techniques and OARs was observed. However, we recommend MIT as a priority technique due to the ability to protect OARs, ease of administration during treatment, and the fact that the patient stays in the treatment unit for a shorter period of time.

Quantitative and dosimetric analysis for treating synchronous bilateral breast cancer using two radiotherapy planning techniques

University of Health Sciences Istanbul Training and Research Hospital

Department of Radiation Oncology, MNT Health Services Medical Physicist

Polish Journal of Medical Physics and Engineering

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

Objective: We compared mono-isocenter and dual-isocenter plans in synchronous bilateral breast cancer (SBBC), which is defined as tumours occurring...

Quantitative and dosimetric analysis for treating synchronous bilateral breast cancer using two radiotherapy planning techniques

Published Online: Sep 27, 2021

Page range: 201 - 206

DOI: https://doi.org/10.2478/pjmpe-2021-0024

Keywords
dosimetric comparison, mono-isocenter, dual-isocenter, synchronous bilateral breast cancer

© 2021 Özlem Mermut et al., published by Sciendo

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

Quantitative and dosimetric analysis for treating synchronous bilateral breast cancer using two radiotherapy planning techniques

Published Online: Sep 27, 2021

Page range: 201 - 206

DOI: https://doi.org/10.2478/pjmpe-2021-0024

Keywordsdosimetric comparison, mono-isocenter, dual-isocenter, synchronous bilateral breast cancer

© 2021 Özlem Mermut et al., published by Sciendo

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

Keywords
dosimetric comparison, mono-isocenter, dual-isocenter, synchronous bilateral breast cancer