PMID- 31998635 OWN - NLM STAT- PubMed-not-MEDLINE LR - 20200929 IS - 2234-943X (Print) IS - 2234-943X (Electronic) IS - 2234-943X (Linking) VI - 9 DP - 2019 TI - Heart and Cardiac Substructure Dose Sparing in Synchronous Bilateral Breast Radiotherapy: A Dosimetric Study of Proton and Photon Radiation Therapy. PG - 1456 LID - 10.3389/fonc.2019.01456 [doi] LID - 1456 AB - Background: Synchronous bilateral breast cancer (SBBC) is rare. The purpose of this study was to compare the dosimetric differences in intensity-modulated radiation therapy (IMRT), volumetric-modulated arc therapy (VMAT), helical tomotherapy (HT), and intensity-modulated proton therapy (IMPT) to find an optimal radiotherapy technique for bilateral breast cancer radiotherapy. Methods: For 11 patients who received synchronous bilateral whole-breast irradiation without local lymph nodal regions, six plans were designed for each patient: IMRT with a single isocenter (IMRT-ISO1), IMRT with two isocenters (IMRT-ISO2), VMAT with a single isocenter (VMAT-ISO1), VMAT with two isocenters (VMAT-ISO2), HT, and IMPT. The differences between the single- and dual-isocentric plans for IMRT and VMAT were compared, and the plan with the better quality was selected for further dosimetric comparisons with IMPT and HT. The plan aimed for a target coverage of at least 95% with the prescription dose of 50 Gy [relative biological effectiveness (RBE)] while minimizing the dose of organs at risk (OARs). Results: IMRT-ISO1 and VMAT-ISO2 plans were adopted for further dosimetric comparisons because of the reduced dose of the heart and/or lungs compared to IMRT-ISO2 and VMAT-ISO1 plans. The dose coverage of the planning target volume (PTV) was significantly higher in IMPT plans than that in all other plans. VMAT and IMPT plans showed the best conformity, whereas IMRT plans showed the worst conformity. Compared to IMRT and VMAT plans, IMPT and HT plans achieved significantly higher dose homogeneity. IMPT plans reduced the mean dose and low dose volume (V(5), V(10), and V(20)) of the heart, left anterior descending artery (LAD), and left ventricle (LV). In high-dose volumes of the heart and cardiac substructures, the IMPT, VMAT, and HT techniques showed similar advantages, and IMRT plans increased the values more than other techniques. IMPT plans had the maximal lung and normal tissue sparing but increased the skin dose compared to IMRT and VMAT plans. Conclusions: IMPT plans improve both the target coverage and the OARs sparing, especially for the heart, cardiac substructures (LAD and LV), lungs and normal tissue, in synchronous bilateral breast radiotherapy. VMAT and HT could be selected as suboptimal techniques for SBBC patients. CI - Copyright (c) 2020 Sun, Lin, Tong, Liu, Pan, Tao, Duan and Yin. FAU - Sun, Tao AU - Sun T AD - Department of Radiation Physics, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China. FAU - Lin, Xiutong AU - Lin X AD - Department of Radiation Physics, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China. FAU - Tong, Ying AU - Tong Y AD - Department of Radiation Physics, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China. FAU - Liu, Xiao AU - Liu X AD - Department of Radiation Physics, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China. FAU - Pan, Lingjing AU - Pan L AD - Department of Radiation Oncology, Hefei Ion Medical Center, Hefei, China. FAU - Tao, Cheng AU - Tao C AD - Department of Radiation Physics, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China. FAU - Duan, Jinghao AU - Duan J AD - Department of Radiation Physics, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China. FAU - Yin, Yong AU - Yin Y AD - Department of Radiation Physics, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China. LA - eng PT - Journal Article DEP - 20200110 PL - Switzerland TA - Front Oncol JT - Frontiers in oncology JID - 101568867 PMC - PMC6966409 OTO - NOTNLM OT - dosimetry OT - intensity-modulated radiation therapy OT - proton beam therapy OT - synchronous bilateral breast cancer OT - tomotherapy OT - volumetric-modulated arc therapy EDAT- 2020/01/31 06:00 MHDA- 2020/01/31 06:01 PMCR- 2019/01/01 CRDT- 2020/01/31 06:00 PHST- 2019/06/27 00:00 [received] PHST- 2019/12/05 00:00 [accepted] PHST- 2020/01/31 06:00 [entrez] PHST- 2020/01/31 06:00 [pubmed] PHST- 2020/01/31 06:01 [medline] PHST- 2019/01/01 00:00 [pmc-release] AID - 10.3389/fonc.2019.01456 [doi] PST - epublish SO - Front Oncol. 2020 Jan 10;9:1456. doi: 10.3389/fonc.2019.01456. eCollection 2019.