title: Comparison of adverse effects of proton and X-ray chemoradiotherapy for esophageal cancer using an adaptive dose-volume histogram analysis.
abstract: Cardiopulmonary late toxicity is of concern in concurrent chemoradiotherapy (CCRT) for esophageal cancer. The aim of this study was to examine the benefit of proton beam therapy (PBT) using clinical data and adaptive dose-volume histogram (DVH) analysis. The subjects were 44 patients with esophageal cancer who underwent definitive CCRT using X-rays (n = 19) or protons (n = 25). Experimental recalculation using protons was performed for the patient actually treated with X-rays, and vice versa. Target coverage and dose constraints of normal tissues were conserved. Lung V5-V20, mean lung dose (MLD), and heart V30-V50 were compared for risk organ doses between experimental plans and actual treatment plans. Potential toxicity was estimated using protons in patients actually treated with X-rays, and vice versa. Pulmonary events of Grade ≥2 occurred in 8/44 cases (18%), and cardiac events were seen in 11 cases (25%). Risk organ doses in patients with events of Grade ≥2 were significantly higher than for those with events of Grade ≤1. Risk organ doses were lower in proton plans compared with X-ray plans. All patients suffering toxicity who were treated with X-rays (n = 13) had reduced predicted doses in lung and heart using protons, while doses in all patients treated with protons (n = 24) with toxicity of Grade ≤1 had worsened predicted toxicity with X-rays. Analysis of normal tissue complication probability showed a potential reduction in toxicity by using proton beams. Irradiation dose, volume and adverse effects on the heart and lung can be reduced using protons. Thus, PBT is a promising treatment modality for the management of esophageal cancer.
authors.affiliation: Department of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan maxima@pmrc.tsukuba.ac.jp.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Makishima
authors.affiliation: Department of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ishikawa
authors.affiliation: Department of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Terunuma
authors.affiliation: Department of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Hashimoto
authors.affiliation: Department of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Yamanashi
authors.affiliation: Department of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan.
authors.forename: Takao
authors.initials: T
authors.lastname: Sekiguchi
authors.affiliation: Department of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Mizumoto
authors.affiliation: Department of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Okumura
authors.affiliation: Department of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan.
authors.forename: Takeji
authors.initials: T
authors.lastname: Sakae
authors.affiliation: Department of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8576, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Sakurai
mesh_terms: D059248:Chemoradiotherapy / Q000009:adverse effects; D003627:Data Interpretation, Statistical; D004938:Esophageal Neoplasms / Q000628:therapy*; D005260:Female; D006335:Heart Injuries / Q000209:etiology*; D006801:Humans; D055370:Lung Injury / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D061766:Proton Therapy / Q000009:adverse effects*; D011522:Protons / Q000009:adverse effects; D011832:Radiation Injuries / Q000209:etiology*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D016896:Treatment Outcome; D047368:Tumor Burden / Q000528:radiation effects; D014964:X-Ray Therapy / Q000009:adverse effects*; D014965:X-Rays / Q000009:adverse effects
chemical_list: D011522:Protons
keywords: DVH analysis; concurrent chemoradiotherapy; deformation adaptation; esophageal cancer; proton beam therapy