title: Comparison of dose-volume histograms between proton beam and X-ray conformal radiotherapy for locally advanced non-small-cell lung cancer.
abstract: The purpose of this study was to compare the parameters of the dose-volume histogram (DVH) between proton beam therapy (PBT) and X-ray conformal radiotherapy (XCRT) for locally advanced non-small-cell lung cancer (NSCLC), according to the tumor conditions. A total of 35 patients having NSCLC treated with PBT were enrolled in this analysis. The numbers of TNM stage and lymph node status were IIB (n = 3), IIIA (n = 15) and IIIB (n = 17), and N0 (n = 2), N1 (n = 4), N2 (n = 17) and N3 (n = 12), respectively. Plans for XCRT were simulated based on the same CT, and the same clinical target volume (CTV) was used based on the actual PBT plan. The treatment dose was 74 Gy-equivalent dose (GyE) for the primary site and 66 GyE for positive lymph nodes. The parameters were then calculated according to the normal lung dose, and the irradiation volumes of the doses (Vx) were compared. We also evaluated the feasibility of both plans according to criteria: V5 ≥ 42%, V20 ≥ 25%, mean lung dose ≥ 20 Gy. The mean normal lung dose and V5 to V50 were significantly lower in PBT than in XCRT. The differences were greater with the more advanced nodal status and with the larger CTV. Furthermore, 45.7% of the X-ray plans were classified as inadequate according to the criteria, whereas 17.1% of the proton plans were considered unsuitable. The number of inadequate X-ray plans increased in cases with advanced nodal stage. This study indicated that some patients who cannot receive photon radiotherapy may be able to be treated using PBT.
authors.affiliation: Departments of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan ohno@pmrc.tsukuba.ac.jp.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Ohno
authors.affiliation: Departments of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Oshiro
authors.affiliation: Departments of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Mizumoto
authors.affiliation: Departments of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan.
authors.forename: Haruko
authors.initials: H
authors.lastname: Numajiri
authors.affiliation: Departments of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ishikawa
authors.affiliation: Departments of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Okumura
authors.affiliation: Departments of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Terunuma
authors.affiliation: Departments of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan.
authors.forename: Takeji
authors.initials: T
authors.lastname: Sakae
authors.affiliation: Departments of Radiation Oncology and Proton Medical Research Center, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Sakurai
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000473:pathology* / Q000532:radiotherapy*; D004307:Dose-Response Relationship, Radiation; D005240:Feasibility Studies; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology* / Q000532:radiotherapy*; D061766:Proton Therapy; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods*; D011882:Radiotherapy, High-Energy / Q000379:methods*; D016896:Treatment Outcome; D047368:Tumor Burden / Q000528:radiation effects; D014965:X-Rays; D011522:Protons
chemical_list: D011522:Protons
keywords: DVH; dose escalation; locally advanced NSCLC; proton therapy