title: Changes in pulmonary function after three-dimensional conformal radiotherapy, intensity-modulated radiotherapy, or proton beam therapy for non-small-cell lung cancer.
abstract: OBJECTIVE
  To investigate the extent of change in pulmonary function over time after definitive radiotherapy for non-small-cell lung cancer (NSCLC) with modern techniques and to identify predictors of changes in pulmonary function according to patient, tumor, and treatment characteristics.
  
  
  METHODS
  We analyzed 250 patients who had received ≥ 60 Gy radio(chemo)therapy for primary NSCLC in 1998-2010 and had undergone pulmonary function tests before and within 1 year after treatment. Ninety-three patients were treated with three-dimensional conformal radiotherapy, 97 with intensity-modulated radiotherapy, and 60 with proton beam therapy. Postradiation pulmonary function test values were evaluated among individual patients compared with the same patient's preradiation value at the following time intervals: 0-4 (T1), 5-8 (T2), and 9-12 (T3) months.
  
  
  RESULTS
  Lung diffusing capacity for carbon monoxide (DLCO) was reduced in the majority of patients along the three time periods after radiation, whereas the forced expiratory volume in 1 s per unit of vital capacity (FEV1/VC) showed an increase and decrease after radiation in a similar percentage of patients. There were baseline differences (stage, radiotherapy dose, concurrent chemotherapy) among the radiation technology groups. On multivariate analysis, the following features were associated with larger posttreatment declines in DLCO: pretreatment DLCO, gross tumor volume, lung and heart dosimetric data, and total radiation dose. Only pretreatment DLCO was associated with larger posttreatment declines in FEV1/VC.
  
  
  CONCLUSIONS
  Lung diffusing capacity for carbon monoxide is reduced in the majority of patients after radiotherapy with modern techniques. Multiple factors, including gross tumor volume, preradiation lung function, and dosimetric parameters, are associated with the DLCO decline. Prospective studies are needed to better understand whether new radiation technology, such as proton beam therapy or intensity-modulated radiotherapy, may decrease the pulmonary impairment through greater lung sparing.
authors.affiliation: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.
authors.forename: Jose L
authors.initials: JL
authors.lastname: Lopez Guerra
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Gomez
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhuang
authors.forename: Lawrence B
authors.initials: LB
authors.lastname: Levy
authors.forename: George
authors.initials: G
authors.lastname: Eapen
authors.forename: Hongmei
authors.initials: H
authors.lastname: Liu
authors.forename: Radhe
authors.initials: R
authors.lastname: Mohan
authors.forename: Ritsuko
authors.initials: R
authors.lastname: Komaki
authors.forename: James D
authors.initials: JD
authors.lastname: Cox
authors.forename: Zhongxing
authors.initials: Z
authors.lastname: Liao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000704:Analysis of Variance; D002248:Carbon Monoxide / Q000378:metabolism; D002289:Carcinoma, Non-Small-Cell Lung / Q000503:physiopathology / Q000532:radiotherapy*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008168:Lung / Q000503:physiopathology / Q000528:radiation effects*; D008175:Lung Neoplasms / Q000503:physiopathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D061766:Proton Therapy; D011653:Pulmonary Diffusing Capacity / Q000502:physiology / Q000528:radiation effects*; D020266:Radiotherapy, Conformal / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated; D012129:Respiratory Function Tests; D012189:Retrospective Studies; D014797:Vital Capacity / Q000502:physiology
chemical_list: D002248:Carbon Monoxide