title: Change in diffusing capacity after radiation as an objective measure for grading radiation pneumonitis in patients treated for non-small-cell lung cancer.
abstract: OBJECTIVE
  Scoring of radiation pneumonitis (RP), a dose-limiting toxicity after thoracic radiochemotherapy, is subjective and thus inconsistent among studies. Here we investigated whether the extent of change in diffusing capacity of the lung for carbon monoxide (DLCO) after radiation therapy (RT) for non-small-cell lung cancer (NSCLC) could be used as an objective means of quantifying RP.
  
  
  METHODS
  We analyzed potential correlations between DLCO and RP in 140 patients who received definitive RT (≥ 60 Gy) with or without chemotherapy for primary NSCLC. All underwent DLCO analysis before and after RT. Post-RT DLCO values within 1 week of the RP diagnosis (Grade 0, 1, 2, or 3) were selected and compared with that individual's preradiation values. Percent reductions in DLCO and RP grade were compared by point biserial correlation in the entire patient group and in subgroups stratified according to various clinical factors.
  
  
  RESULTS
  Patients experiencing Grade 0, 1, 2, or 3 RP had median percentage changes in DLCO after RT of 10.7%, 13%, 22.1%, or 35.2%. Percent reduction in DLCO correlated with RP Grade ≤ 1 vs. ≥ 2 (p = 0.0004). This association held for the following subgroups: age ≥ 65 years, advanced stage, smokers, use of chemotherapy, volume of normal lung receiving at least 20 Gy ≥ 30%, and baseline DLCO or forced expiratory volume in 1 second ≥ 60%.
  
  
  CONCLUSIONS
  By correlating percent change in DLCO from pretreatment values at the time of diagnosis of RP with RP grade, we were able to identify categories of RP based on the change in DLCO. These criteria provide a basis for an objective scoring system for RP based on change in DLCO.
authors: Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors: Jose Luis
authors: JL
authors: Lopez Guerra
authors: Daniel
authors: D
authors: Gomez
authors: Yan
authors: Y
authors: Zhuang
authors: Lawrence B
authors: LB
authors: Levy
authors: George
authors: G
authors: Eapen
authors: Hongmei
authors: H
authors: Liu
authors: Radhe
authors: R
authors: Mohan
authors: Ritsuko
authors: R
authors: Komaki
authors: James D
authors: JD
authors: Cox
authors: Zhongxing
authors: Z
authors: Liao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002248:Carbon Monoxide / Q000378:metabolism; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000503:physiopathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000503:physiopathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011653:Pulmonary Diffusing Capacity / Q000502:physiology / Q000528:radiation effects*; D017564:Radiation Pneumonitis / Q000175:diagnosis* / Q000503:physiopathology
chemical_list: D002248:Carbon Monoxide