Internal mammary node irradiation in early breast cancer – target coverage and implications on dose to organs at risk
Purpose: Indications for radiotherapy (RT) of the internal mammary nodes (IMN) in early breast cancer vary between countries. While studies indicate benefits, IMN RT increases the dose to the heart and lungs, and the risk-benefit ratio of this treatment is debated. This study investigates how IMN RT...
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| Language: | English |
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Medical Journals Sweden
2025-07-01
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| Series: | Acta Oncologica |
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| Online Access: | https://medicaljournalssweden.se/actaoncologica/article/view/43716 |
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| author | Lovisa Berg Jeanette Sporre Elisabeth Kjellén Sofie Ceberg Elinore Wieslander Sara Alkner |
| author_facet | Lovisa Berg Jeanette Sporre Elisabeth Kjellén Sofie Ceberg Elinore Wieslander Sara Alkner |
| author_sort | Lovisa Berg |
| collection | DOAJ |
| description | Purpose: Indications for radiotherapy (RT) of the internal mammary nodes (IMN) in early breast cancer vary between countries. While studies indicate benefits, IMN RT increases the dose to the heart and lungs, and the risk-benefit ratio of this treatment is debated. This study investigates how IMN RT affects dose to organs at risk (OAR) and pneumonitis incidence in a clinical setting.
Methods: This retrospective study includes breast cancer patients receiving adjuvant locoregional RT with and without IMN included in the target volume at Skåne University Hospital, Sweden, from 2018 to 2021. Treatment plans followed national dose-volume criteria, prioritizing lung and heart over IMN coverage. A total of 247 treatment plans for locoregional RT with IMN were compared to 397 without. Dose to OAR, IMN coverage and pneumonitis incidence were investigated.
Results: The mean ipsilateral lung dose increased by 2.7 Gy with IMN RT (p < 0.001), and the mean heart dose (left-sided treatment) by 0.5 Gy (p < 0.001). Both irradiated and treated volume in relation to planning target volume (PTV) increased with ~20% (p < 0.001). Desired IMN coverage was achieved in 76% of the plans, with lung dose exceeding recommended constraints as the primary reason for decreased target coverage in the remaining plans. Of the 220 patients with follow-up of ≥6 months, 2 (0.9%) were diagnosed with pneumonitis grade 2.
Interpretation: Introduction of IMN RT primarily resulted in an increased lung dose. However, rate of symptomatic pneumonitis was low. Most patients achieved desired IMN coverage using 3D-CRT, with lung dose being the limiting factor.
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| format | Article |
| id | doaj-art-471dfebdad9646c282471ca05ff35d4a |
| institution | Kabale University |
| issn | 1651-226X |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Medical Journals Sweden |
| record_format | Article |
| series | Acta Oncologica |
| spelling | doaj-art-471dfebdad9646c282471ca05ff35d4a2025-08-20T03:34:44ZengMedical Journals SwedenActa Oncologica1651-226X2025-07-016410.2340/1651-226X.2025.43716Internal mammary node irradiation in early breast cancer – target coverage and implications on dose to organs at riskLovisa Berg0https://orcid.org/0009-0009-5416-6763Jeanette Sporre1Elisabeth Kjellén2Sofie Ceberg3https://orcid.org/0009-0004-0192-4632Elinore Wieslander4https://orcid.org/0000-0003-1187-7150Sara Alkner5https://orcid.org/0000-0001-8683-9971Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden; Department of Oncology, Institute of Clinical Sciences, Faculty of Medicine, Lund University, Lund, SwedenClinic of Oncology, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, SwedenClinic of Oncology, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, SwedenMedical Radiation Physics, Department of Clinical Sciences Lund, Lund University, Lund, SwedenRadiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, SwedenDepartment of Oncology, Institute of Clinical Sciences, Faculty of Medicine, Lund University, Lund, Sweden; Clinic of Oncology, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, SwedenPurpose: Indications for radiotherapy (RT) of the internal mammary nodes (IMN) in early breast cancer vary between countries. While studies indicate benefits, IMN RT increases the dose to the heart and lungs, and the risk-benefit ratio of this treatment is debated. This study investigates how IMN RT affects dose to organs at risk (OAR) and pneumonitis incidence in a clinical setting. Methods: This retrospective study includes breast cancer patients receiving adjuvant locoregional RT with and without IMN included in the target volume at Skåne University Hospital, Sweden, from 2018 to 2021. Treatment plans followed national dose-volume criteria, prioritizing lung and heart over IMN coverage. A total of 247 treatment plans for locoregional RT with IMN were compared to 397 without. Dose to OAR, IMN coverage and pneumonitis incidence were investigated. Results: The mean ipsilateral lung dose increased by 2.7 Gy with IMN RT (p < 0.001), and the mean heart dose (left-sided treatment) by 0.5 Gy (p < 0.001). Both irradiated and treated volume in relation to planning target volume (PTV) increased with ~20% (p < 0.001). Desired IMN coverage was achieved in 76% of the plans, with lung dose exceeding recommended constraints as the primary reason for decreased target coverage in the remaining plans. Of the 220 patients with follow-up of ≥6 months, 2 (0.9%) were diagnosed with pneumonitis grade 2. Interpretation: Introduction of IMN RT primarily resulted in an increased lung dose. However, rate of symptomatic pneumonitis was low. Most patients achieved desired IMN coverage using 3D-CRT, with lung dose being the limiting factor. https://medicaljournalssweden.se/actaoncologica/article/view/43716Breast canceradjuvant radiotherapyinternal mammary nodetreatment planning |
| spellingShingle | Lovisa Berg Jeanette Sporre Elisabeth Kjellén Sofie Ceberg Elinore Wieslander Sara Alkner Internal mammary node irradiation in early breast cancer – target coverage and implications on dose to organs at risk Acta Oncologica Breast cancer adjuvant radiotherapy internal mammary node treatment planning |
| title | Internal mammary node irradiation in early breast cancer – target coverage and implications on dose to organs at risk |
| title_full | Internal mammary node irradiation in early breast cancer – target coverage and implications on dose to organs at risk |
| title_fullStr | Internal mammary node irradiation in early breast cancer – target coverage and implications on dose to organs at risk |
| title_full_unstemmed | Internal mammary node irradiation in early breast cancer – target coverage and implications on dose to organs at risk |
| title_short | Internal mammary node irradiation in early breast cancer – target coverage and implications on dose to organs at risk |
| title_sort | internal mammary node irradiation in early breast cancer target coverage and implications on dose to organs at risk |
| topic | Breast cancer adjuvant radiotherapy internal mammary node treatment planning |
| url | https://medicaljournalssweden.se/actaoncologica/article/view/43716 |
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