title: The clinical results of proton beam therapy in patients with idiopathic pulmonary fibrosis: a single center experience.
abstract: BACKGROUND
  The purpose of this study is to retrospectively evaluate the incidence of lung toxicities after proton beam therapy (PBT) in patients with idiopathic pulmonary fibrosis (IPF).
  
  
  METHODS
  Patients diagnosed with primary lung cancer or lung metastasis who were treated with PBT between January 2009 and May 2015 were recruited from our database retrospectively. Cases of pneumonitis (excluding infection-related pneumonitis) were evaluated using the Common Terminology Criteria for Adverse Events version 4.0, and the Fletcher-Hugh-Jones classification of respiratory status was used to evaluate pretreatment and posttreatment respiratory function.
  
  
  RESULTS
  Sixteen IPF patients received PBT for lung tumors, 15 received PBT for primary lung cancer, and one patient received PBT for metastasis from lung cancer. The cohort was composed of 14 men and 2 women, with a median age of 76 years (range: 63-89 years). The median follow-up time was 12 months (range: 4-39 months). The median dose of PBT was 80.0 Gy relative biological dose effectiveness (RBE) (range: 66.0-86.4 Gy [RBE]). The cumulative incidence of pneumonitis was 19.8 % (95 % confidence interval [CI]: 0-40.0 %), including one case of grade 5 pneumonitis. Reduced respiratory function was observed after PBT in seven patients, including one patient with pleural dissemination; five of these patients required home oxygen therapy.
  
  
  CONCLUSIONS
  This study suggests that PBT can be performed more safely in IPF patients than surgery or X-ray irradiation. Although PBT has become a treatment choice for lung tumors of patients with IPF, the adverse events warrant serious attention.
authors.affiliation: Department of Radiation Oncology, Southern Tohoku Proton Therapy Center, 7-172, Yatsuyamada, Koriyama, Fukushima, 963-8052, Japan. abc1123513@gmail.com.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ono
authors.affiliation: Department of Radiation Oncology, Sapporo Teishinkai Hospital, 1-3-1, Kita33johigashi, Higashi, Sapporo, Hokkaido, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Hareyama
authors.affiliation: Department of Radiation Oncology, Southern Tohoku Proton Therapy Center, 7-172, Yatsuyamada, Koriyama, Fukushima, 963-8052, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Department of Radiation Oncology, Southern Tohoku Proton Therapy Center, 7-172, Yatsuyamada, Koriyama, Fukushima, 963-8052, Japan.
authors.forename: Kanako
authors.initials: K
authors.lastname: Kimura
authors.affiliation: Department of Radiation Oncology, Southern Tohoku Proton Therapy Center, 7-172, Yatsuyamada, Koriyama, Fukushima, 963-8052, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Hayashi
authors.affiliation: Department of Radiation Oncology, Southern Tohoku Proton Therapy Center, 7-172, Yatsuyamada, Koriyama, Fukushima, 963-8052, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Azami
authors.affiliation: Department of Radiation Oncology, Southern Tohoku Proton Therapy Center, 7-172, Yatsuyamada, Koriyama, Fukushima, 963-8052, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Hirose
authors.affiliation: Department of Radiation Oncology, Hirosaki University Faculty of Medicine, 5, Zaifu-cho, Hirosaki, Aomori, Japan.
authors.forename: Yoshiomi
authors.initials: Y
authors.lastname: Hatayama
authors.affiliation: Department of Radiation Oncology, Southern Tohoku Proton Therapy Center, 7-172, Yatsuyamada, Koriyama, Fukushima, 963-8052, Japan.
authors.forename: Motohisa
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Department of Radiation Oncology, Southern Tohoku Proton Therapy Center, 7-172, Yatsuyamada, Koriyama, Fukushima, 963-8052, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Wada
authors.affiliation: Department of Radiation Oncology, Southern Tohoku Proton Therapy Center, 7-172, Yatsuyamada, Koriyama, Fukushima, 963-8052, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kikuchi
authors.affiliation: Department of Radiation Oncology, Yamagata University Faculty of Medicine, 2-2-2, Iida-Nishi, Yamagata, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Nemoto
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000175:diagnosis* / Q000209:etiology; D008168:Lung / Q000528:radiation effects; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D061214:Patient Safety; D000072078:Positron Emission Tomography Computed Tomography; D061766:Proton Therapy / Q000379:methods*; D017564:Radiation Pneumonitis / Q000175:diagnosis* / Q000209:etiology; D012119:Respiration; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: Idiopathic interstitial pneumonias; Idiopathic pulmonary fibrosis; Lung neoplasms; Protons; Radiation pneumonitis