title: Impact of 3D conformal radiotherapy on lung function of patients with lung cancer: a prospective study.
abstract: BACKGROUND
  The development of three-dimensional conformal radiotherapy (3D-RT) has enabled the restriction of the dose to normal lung, limiting radiation-induced lung injury.
  
  
  OBJECTIVE
  This study was designed to describe the time course of lung function until 7.5 months after 3D-RT in patients with lung cancer, and assess the relationship between lung function changes and dose-volume histogram (DVH) analysis or computed tomography scan changes. Radiation doses were optimized according to recent guidelines.
  
  
  METHODS
  Sixty-five lung cancer patients treated with 3D-RT agreed to participate in this prospective, hospital-based study. Lung volumes, forced expiratory volume in 1 s (FEV1) and diffusing capacity of the lung for carbon monoxide (DLCO) were measured before radiotherapy (RT), 10 weeks, 4 and 7.5 months after the beginning of 3D-RT.
  
  
  RESULTS
  Eleven lung cancer patients (17%) developed grade 2-3 respiratory symptoms after RT. At 7.5 months, vital capacity (VC) was 96 ± 2%, total lung capacity (TLC) 95 ± 2%, FEV1 93 ± 2% and DLCO 90 ± 2% of the initial value. Only 15% of patients showed pulmonary function reduction > 20%. Patients with FEV1 or DLCO < 60% before RT did not show significant changes after RT. There were weak correlations between reduction of VC, TLC, FEV1 or DLCO and radiation dosimetric parameters and between reduction of VC or FEV1 and radiation-induced pneumonitis images.
  
  
  CONCLUSIONS
  In lung cancer, the reduction of lung function within 7.5 months after 3D-RT was small and correlated, albeit weakly, with DVH parameters. Patients with initially impaired lung function showed tiny changes in spirometry and DLCO values.
authors.affiliation: Pôle de Pathologie Thoracique, Hôpitaux Universitaires, Université de Strasbourg, Faculté de Médecine, Strasbourg, France.
authors.forename: Irina
authors.initials: I
authors.lastname: Enache
authors.forename: Georges
authors.initials: G
authors.lastname: Noel
authors.forename: Mi Young
authors.initials: MY
authors.lastname: Jeung
authors.forename: Nicolas
authors.initials: N
authors.lastname: Meyer
authors.forename: Monique
authors.initials: M
authors.lastname: Oswald-Mammosser
authors.forename: Cristina
authors.initials: C
authors.lastname: Pistea
authors.forename: Guy-Michel
authors.initials: GM
authors.lastname: Jung
authors.forename: Bertrand
authors.initials: B
authors.lastname: Mennecier
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Quoix
authors.forename: Anne
authors.initials: A
authors.lastname: Charloux
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000175:diagnosis / Q000503:physiopathology / Q000532:radiotherapy*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D005541:Forced Expiratory Volume / Q000528:radiation effects*; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis / Q000503:physiopathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011446:Prospective Studies; D020266:Radiotherapy, Conformal / Q000379:methods*; D012129:Respiratory Function Tests; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome