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Skin dose in post-mastectomy radiotherapy – a comparative analysis of field-in-field intensity modulated radiotherapy and volumetric modulated arc therapy

Ali, T. ; Pignol, J. P. ; Fishawy, M. Al ; Salmi, F. Al ; Mandhari, Z. Al ; Amri, I. Al ; Lopes, A. P.Galerani and af Rosenschold, P. Munck LU orcid (2026) In Physica Medica 148.
Abstract

Background and Purpose Post-mastectomy radiotherapy (PMRT) improves both the locoregional control and survival in advanced breast cancer. While the use of bolus can enhance skin dose, many oncologists prefer not to use it because of the dramatic increase in skin toxicity. The optimal technique to ensure adequate skin dose is unknown, and this study compares the superficial dose for three techniques — field-in-field intensity modulated radiotherapy (FIF-IMRT), volumetric-modulated arc therapy (VMAT), and flattening-filter-free volumetric-modulated arc therapy (FFF-VMAT) — in patients receiving only PMRT without bolus. Methods CT simulation data of 51 post-mastectomy patients treated between 2023 and 2024 were acquired. For each patient,... (More)

Background and Purpose Post-mastectomy radiotherapy (PMRT) improves both the locoregional control and survival in advanced breast cancer. While the use of bolus can enhance skin dose, many oncologists prefer not to use it because of the dramatic increase in skin toxicity. The optimal technique to ensure adequate skin dose is unknown, and this study compares the superficial dose for three techniques — field-in-field intensity modulated radiotherapy (FIF-IMRT), volumetric-modulated arc therapy (VMAT), and flattening-filter-free volumetric-modulated arc therapy (FFF-VMAT) — in patients receiving only PMRT without bolus. Methods CT simulation data of 51 post-mastectomy patients treated between 2023 and 2024 were acquired. For each patient, three plans (FIF-IMRT, VMAT, FFF-VMAT) were generated using 6 MV beams with the Anisotropic Analytical Algorithm (AAA) for dose calculation. The skin target volume was defined as a 2 to 5 mm subcutaneous layer. Dosimetric endpoints included skin V90%, mean dose, Dmin1cc, and PTV_eval V90% and V105%. Statistical analysis used was the Friedman test with significance set at p < 0.001. Results 153 plans were generated. FIF-IMRT systematically demonstrated superior skin coverage: median skin V90% was 81.6% vs. 61.5% (FFF-VMAT) and 57.0% (VMAT); median mean skin dose was 94.6% (FIF-IMRT) vs. 90.7% (FFF-VMAT) and 90.1% (VMAT). Dmin1cc was also the highest with FIF-IMRT. Differences were all statistically significant (p < 0.001). The PTV_eval dose was more homogeneous with VMAT and FFF-VMAT, and a 2.1% increase of V105% with FIF-IMRT was deemed clinically acceptable. Conclusion In the absence of a bolus, FIF-IMRT systematically provides superior and consistent coverage of the superficial dermis compared to VMAT-based techniques.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Breast cancer, External beam radiotherapy, Post mastectomy radiotherapy, Skin dose
in
Physica Medica
volume
148
article number
105861
publisher
Associazione Italiana di Fisica Medica
external identifiers
  • pmid:42296890
  • scopus:105041632877
ISSN
1120-1797
DOI
10.1016/j.ejmp.2026.105861
language
English
LU publication?
yes
id
24b96ced-f9c8-4e15-9325-58a922108609
date added to LUP
2026-07-01 12:29:51
date last changed
2026-07-02 03:18:27
@article{24b96ced-f9c8-4e15-9325-58a922108609,
  abstract     = {{<p>Background and Purpose Post-mastectomy radiotherapy (PMRT) improves both the locoregional control and survival in advanced breast cancer. While the use of bolus can enhance skin dose, many oncologists prefer not to use it because of the dramatic increase in skin toxicity. The optimal technique to ensure adequate skin dose is unknown, and this study compares the superficial dose for three techniques — field-in-field intensity modulated radiotherapy (FIF-IMRT), volumetric-modulated arc therapy (VMAT), and flattening-filter-free volumetric-modulated arc therapy (FFF-VMAT) — in patients receiving only PMRT without bolus. Methods CT simulation data of 51 post-mastectomy patients treated between 2023 and 2024 were acquired. For each patient, three plans (FIF-IMRT, VMAT, FFF-VMAT) were generated using 6 MV beams with the Anisotropic Analytical Algorithm (AAA) for dose calculation. The skin target volume was defined as a 2 to 5 mm subcutaneous layer. Dosimetric endpoints included skin V<sub>90%</sub>, mean dose, D<sub>min1cc</sub>, and PTV_eval V<sub>90%</sub> and V<sub>105%</sub>. Statistical analysis used was the Friedman test with significance set at p &lt; 0.001. Results 153 plans were generated. FIF-IMRT systematically demonstrated superior skin coverage: median skin V<sub>90%</sub> was 81.6% vs. 61.5% (FFF-VMAT) and 57.0% (VMAT); median mean skin dose was 94.6% (FIF-IMRT) vs. 90.7% (FFF-VMAT) and 90.1% (VMAT). D<sub>min1cc</sub> was also the highest with FIF-IMRT. Differences were all statistically significant (p &lt; 0.001). The PTV_eval dose was more homogeneous with VMAT and FFF-VMAT, and a 2.1% increase of V<sub>105%</sub> with FIF-IMRT was deemed clinically acceptable. Conclusion In the absence of a bolus, FIF-IMRT systematically provides superior and consistent coverage of the superficial dermis compared to VMAT-based techniques.</p>}},
  author       = {{Ali, T. and Pignol, J. P. and Fishawy, M. Al and Salmi, F. Al and Mandhari, Z. Al and Amri, I. Al and Lopes, A. P.Galerani and af Rosenschold, P. Munck}},
  issn         = {{1120-1797}},
  keywords     = {{Breast cancer; External beam radiotherapy; Post mastectomy radiotherapy; Skin dose}},
  language     = {{eng}},
  publisher    = {{Associazione Italiana di Fisica Medica}},
  series       = {{Physica Medica}},
  title        = {{Skin dose in post-mastectomy radiotherapy – a comparative analysis of field-in-field intensity modulated radiotherapy and volumetric modulated arc therapy}},
  url          = {{http://dx.doi.org/10.1016/j.ejmp.2026.105861}},
  doi          = {{10.1016/j.ejmp.2026.105861}},
  volume       = {{148}},
  year         = {{2026}},
}