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Taparra K, Lester SC, Harmsen WS, Petersen M, Funk RK, Blanchard MJ, Young P, Herrmann J, Hunzeker A, Schultz H, McCollough C, Tasson A, Leng S, Martenson JA, Whitaker TJ, Williamson E, Laack NN. Reducing Heart Dose with Protons and Cardiac Substructure Sparing for Mediastinal Lymphoma Treatment. Int J Part Ther 2020; 7:1-12. [PMID: 33094130 PMCID: PMC7574827 DOI: 10.14338/ijpt-20-00010.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 06/15/2020] [Indexed: 12/25/2022] Open
Abstract
Purpose Electrocardiogram-gated computed tomography with coronary angiography can be used for cardiac substructure sparing (CSS) optimization, which identifies and improves avoidance of cardiac substructures when treating with intensity modulated radiotherapy (IMRT). We investigated whether intensity modulated proton therapy (IMPT) would further reduce dose to cardiac substructures for patients with mediastinal lymphoma. Patients and Methods Twenty-one patients with mediastinal lymphoma were enrolled and underwent electrocardiogram-gated computed tomography angiography during or shortly after simulation for radiotherapy planning. Thirteen patients with delineated cardiac substructures underwent comparative planning with both IMPT and IMRT. Plans were normalized for equivalent (95%) target volume coverage for treatment comparison. Results Thirteen patients met criteria for this study. The median size of the mediastinal lymphadenopathy was 7.9 cm at the greatest diameter. Compared with IMRT-CSS, IMPT-CSS significantly reduced mean dose to all cardiac substructures, including 3 coronary arteries and 4 cardiac valves. Use of IMPT significantly reduced average whole-heart dose from 9.6 to 4.9 Gy (P < .0001), and average mean lung dose was 9.7 vs 5.8 Gy (P < .0001). Prospectively defined clinically meaningful improvement was observed in at least 1 coronary artery in 9 patients (69%), at least 1 cardiac valve in 10 patients (77%), and whole heart in all 13 patients. Conclusions For patients with mediastinal lymphoma, IMPT-CSS treatment planning significantly reduced radiation dose to cardiac substructures. The significant improvements outlined in this study for proton therapy suggest possible clinical improvement in alignment with previous analyses of CSS optimization.
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Affiliation(s)
- Kekoa Taparra
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA.,Mayo Clinic Alix School of Medicine, Mayo Clinic, Rochester, MN, USA.,This author contributed to and was responsible for statistical analyses
| | - Scott C Lester
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | - W Scott Harmsen
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.,This author contributed to and was responsible for statistical analyses
| | - Molly Petersen
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA.,This author contributed to and was responsible for statistical analyses
| | - Ryan K Funk
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | | | - Phillip Young
- Department of Diagnostic Radiology, Mayo Clinic, Rochester, MN, USA
| | - Joerg Herrmann
- Department of Cardiology, Mayo Clinic, Rochester, MN, USA
| | - Ashley Hunzeker
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | - Heather Schultz
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
| | | | | | - Shuai Leng
- Department of Diagnostic Radiology, Mayo Clinic, Rochester, MN, USA
| | | | | | - Eric Williamson
- Department of Diagnostic Radiology, Mayo Clinic, Rochester, MN, USA
| | - Nadia N Laack
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
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