Dosimetric comparison of magnetic resonance-guided radiation therapy, intensity-modulated proton therapy and volumetric-modulated arc therapy for distal esophageal cancer

Andrew R Barsky; Jerry George; Andrew J Wroe; Kathryn E Mittauer; Adeel Kaiser; Roberto Herrera; Jen Yu; Alonso N Gutierrez; Diane Alvarez; James McCulloch; Michael E Kasper; Minesh P Mehta; Michael D Chuong

doi:10.1016/j.meddos.2023.09.004

Dosimetric comparison of magnetic resonance-guided radiation therapy, intensity-modulated proton therapy and volumetric-modulated arc therapy for distal esophageal cancer

Med Dosim. 2024;49(2):121-126. doi: 10.1016/j.meddos.2023.09.004. Epub 2023 Nov 23.

Affiliations

¹ Department of Radiation Oncology, Lynn Cancer Institute, Baptist Health South Florida, Boca Raton, FL 33486, USA. Electronic address: Andrew.Barsky@baptisthealth.net.
² Department of Radiation Oncology, Orlando Health Cancer Institute, Orlando, FL 32806, USA.
³ Department of Radiation Oncology, Miami Cancer Institute, Miami, FL, 33176, USA.
⁴ Department of Radiation Oncology, Lynn Cancer Institute, Baptist Health South Florida, Boca Raton, FL 33486, USA.

PMID: 38001010
DOI: 10.1016/j.meddos.2023.09.004

Abstract

Advances in radiotherapy (RT) technologies permit significant decreases in the dose delivered to organs at risk (OARs) for patients with esophageal cancer (EC). Novel RT modalities such as proton beam therapy (PBT) and magnetic resonance-guided radiotherapy (MRgRT), as well as motion management techniques including breath hold (BH) are expected to further improve the therapeutic ratio. However, to our knowledge, the dosimetric benefits of PBT vs MRgRT vs volumetric-modulated arc therapy (VMAT) have not been directly compared for EC. We performed a retrospective in silico evaluation using the images and datasets of nine distal EC patients who were treated at our institution with a 0.35-Tesla MR linac to 50.4 Gy in 28 fractions in mid-inspiration BH (BH-MRgRT). Comparison free-breathing (FB) intensity-modulated PBT (FB-IMPT) and FB-VMAT plans were retrospectively created using the same prescription dose, target volume coverage goals, and OAR constraints. A 5 mm setup margin was used for all plans. BH-IMPT and BH-VMAT plans were not evaluated as they would not reflect our institutional practice. Planners were blinded to the results of the treatment plans created using different radiation modalities. The primary objective was to compare plan quality, target volume coverage, and OAR doses. All treatment plans met pre-defined target volume coverage and OAR constraints. The median conformity and homogeneity indices between FB-IMPT, BH-MRgRT and FB-VMAT were 1.13, 1.25, and 1.43 (PITV) and 1.04, 1.15, 1.04 (HI), respectively. For FB-IMPT, BH-MRgRT and FB-VMAT the median heart dose metrics were 52.8, 79.3, 146.8 (V_30Gy, cc), 35.5, 43.8, 77.5 (V_40Gy, cc), 16.9, 16.9, 32.5 (V_50Gy, cc) and 6.5, 14.9, 17.3 (mean, Gy), respectively. Lung dose metrics were 8.6, 7.9, 18.5 (V_20Gy, %), and 4.3, 6.3, 11.2 (mean, Gy), respectively. The mean liver dose (Gy) was 6.5, 19.6, 22.2 respectively. Both FB-IMPT and BH-MRgRT achieve substantial reductions in heart, lung, and liver dose compared to FB-VMAT. We plan to evaluate dosimetric outcomes across these RT modalities assuming consistent use of BH.

Keywords: Dosimetry; Esophageal Cancer; MR-guided radiation Therapy; Proton therapy; Radiation oncology.

Publication types

Comparative Study

MeSH terms

Esophageal Neoplasms* / radiotherapy
Humans
Magnetic Resonance Imaging
Organs at Risk
Proton Therapy* / methods
Radiotherapy Dosage*
Radiotherapy Planning, Computer-Assisted / methods
Radiotherapy, Image-Guided* / methods
Radiotherapy, Intensity-Modulated* / methods
Retrospective Studies