title: Severe radiation pneumonitis after lung stereotactic ablative radiation therapy in patients with interstitial lung disease.
abstract: OBJECTIVE
  To investigate the incidence and predictive factors of severe radiation pneumonitis (RP) after stereotactic ablative radiation therapy (SABR) in early-stage lung cancer patients with preexisting radiological interstitial lung disease (ILD).
  
  
  METHODS
  A retrospective analysis of patients with stage I lung cancer treated with SABR from 2009 to 2014 was conducted. Interstitial lung disease diagnosis and grading was based on pretreatment high-resolution computed tomography imaging. A central review of pretreatment computed tomography by a single experienced thoracic radiologist was conducted. Univariate and multivariate analyses were conducted to determine potential predictors of severe RP in patients with ILD.
  
  
  RESULTS
  Among 504 patients treated with SABR in this period, 6% were identified as having preexisting ILD. There was a 4% rate of ≥ grade 3 RP in the entire cohort. Interstitial lung disease was associated with increased risk of ≥ grade 3 RP (32% in ILD+ vs 2% in ILD-, P < .001). Five patients (21%) with ILD developed grade 5 RP. Lower forced expiratory volume in 1 second and forced vital capacity, higher V5Gy and mean lung dose, presence of severe radiological ILD, and combined emphysema were significant predictors of ≥ grade 3 RP on univariate analysis; only forced expiratory volume in 1 second remained on multivariate analysis.
  
  
  CONCLUSIONS
  Interstitial lung disease is associated with an increased risk of severe RP after SABR. Chest imaging should be reviewed for ILD before SABR, and the risk of fatal RP should be carefully weighed against the benefits of SABR in this subgroup.
authors.affiliation: Department of Radiation Oncology, Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada.
authors.forename: Houda
authors.initials: H
authors.lastname: Bahig
authors.affiliation: Department of Radiation Oncology, Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada.
authors.forename: Edith
authors.initials: E
authors.lastname: Filion
authors.affiliation: Department of Radiation Oncology, Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada.
authors.forename: Toni
authors.initials: T
authors.lastname: Vu
authors.affiliation: Department of Radiology, Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada.
authors.forename: Jean
authors.initials: J
authors.lastname: Chalaoui
authors.affiliation: Department of Radiation Oncology, Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada.
authors.forename: Louise
authors.initials: L
authors.lastname: Lambert
authors.affiliation: Department of Radiation Oncology, Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Roberge
authors.affiliation: Department of Internal Medicine, Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada.
authors.forename: Michel
authors.initials: M
authors.lastname: Gagnon
authors.affiliation: Department of Radiation Oncology, Hôpital Maisonneuve-Rosemont, Montréal, QC, Canada.
authors.forename: Bernard
authors.initials: B
authors.lastname: Fortin
authors.affiliation: Department of Radiation Oncology, Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada.
authors.forename: Dominic
authors.initials: D
authors.lastname: Béliveau-Nadeau
authors.affiliation: Department of Radiation Oncology, Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada.
authors.forename: Dominique
authors.initials: D
authors.lastname: Mathieu
authors.affiliation: Department of Radiation Oncology, Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada. Electronic address: marie-pierre.campeau.chum@ssss.gouv.qc.ca.
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Campeau
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008168:Lung / Q000473:pathology*; D017563:Lung Diseases, Interstitial / Q000150:complications* / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D017564:Radiation Pneumonitis / Q000209:etiology*; D011879:Radiotherapy Dosage; D012189:Retrospective Studies