title: Risk factors for severe radiation pneumonitis in lung cancer.
abstract: BACKGROUND
  Risk factors for severe radiation pneumonitis, which often spreads beyond treatment portals and may even be bilateral, have not been fully investigated. The purpose of this study was to identify important factors associated with severe radiation pneumonitis.
  
  
  METHODS
  111 cases of primary lung cancer, treated with radiotherapy or chemoradiotherapy, were retrospectively analyzed.
  
  
  RESULTS
  Severe radiation pneumonitis occurred in 17 cases (15.3%). The ratio of interstitial change in lungs before radiotherapy and radiotherapy to the contralateral mediastinum with > 40 Gy in the radiation pneumonitis group (RP group) was significantly higher than in patients without radiation pneumonitis (control group) (47.1% vs 5.3%; P < 0.001 and 58.8% vs 27.7%; P = 0.037, respectively). Using logistic regression analysis, interstitial changes before radiotherapy and radiotherapy to the contralateral mediastinum of > 40 Gy were significant risk factors associated with severe radiation pneumonitis.
  
  
  CONCLUSIONS
  These data suggest that pre-existing interstitial changes detected by chest radiography or computed tomography and radiotherapy to the contralateral mediastinum (> 40 Gy) may predict the development of severe radiation pneumonitis.
authors.affiliation: Department of Internal Medicine, National Nishi-Gunma Hospital, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Makimoto
authors.forename: S
authors.initials: S
authors.lastname: Tsuchiya
authors.forename: K
authors.initials: K
authors.lastname: Hayakawa
authors.forename: R
authors.initials: R
authors.lastname: Saitoh
authors.forename: M
authors.initials: M
authors.lastname: Mori
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D017564:Radiation Pneumonitis / Q000000981:diagnostic imaging / Q000209:etiology*; D011859:Radiography; D011882:Radiotherapy, High-Energy; D012189:Retrospective Studies; D012307:Risk Factors