Intensity Modulated Proton Therapy Treatment Planning for Postmastectomy Patients with Metallic Port Tissue Expanders

Purpose: Proton beam therapy can significantly reduce cardiopulmonary radiation exposure compared with photon-based techniques in the postmastectomy setting for locally advanced breast cancer. For patients with metallic port tissue expanders, which are commonly placed in patients undergoing a staged...

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Autores principales: Mingyao Zhu, PhD, Katja Langen, PhD, Elizabeth M. Nichols, MD, Yuting Lin, PhD, Stella Flampouri, PhD, Karen D. Godette, MD, Sunil W. Dutta, MD, Mark W. McDonald, MD, Sagar A. Patel, MD
Formato: article
Lenguaje:EN
Publicado: Elsevier 2022
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Acceso en línea:https://doaj.org/article/a6352d3f909c43e0a6da1e895b36484a
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Sumario:Purpose: Proton beam therapy can significantly reduce cardiopulmonary radiation exposure compared with photon-based techniques in the postmastectomy setting for locally advanced breast cancer. For patients with metallic port tissue expanders, which are commonly placed in patients undergoing a staged breast reconstruction, dose uncertainties introduced by the high-density material pose challenges for proton therapy. In this report, we describe an intensity modulated proton therapy planning technique for port avoidance through a hybrid single-field optimization/multifield optimization approach. Methods and Materials: In this planning technique, 3 beams are utilized. For each beam, no proton spot is placed within or distal to the metal port plus a 5 mm margin. Therefore, precise modeling of the metal port is not required, and various tissue expander manufacturers/models are eligible. The blocked area of 1 beam is dosimetrically covered by 1 or 2 of the remaining beams. Multifield optimization is used in the chest wall target region with blockage of any beam, while single-field optimization is used for remainder of chest wall superior/inferior to the port. Results: Using this technique, clinical plans were created for 6 patients. Satisfactory plans were achieved in the 5 patients with port-to-posterior chest wall separations of 1.5 cm or greater, but not in the sixth patient with a 0.7 cm separation. Conclusions: We described a planning technique and the results suggest that the metallic port-to-chest wall distance may be a key parameter for optimal plan design.