title: Classification and Reporting of Late Radiographic Changes After Lung Stereotactic Body Radiotherapy: Proposing a New System.
abstract: Radiation-induced parenchymal lung changes after stereotactic body radiotherapy are common, and can obscure the primary tumor site. In this study we propose a structured radiographic reporting tool for characterization of these changes, pilot its feasibility in a group of radiation oncologists, and test the interrater agreement. We could demonstrate the applicability of the scale, with a fair to moderate agreement.
  
  
  BACKGROUND
  The purpose of the study was to design and pilot a synoptic scale for characterization of late radiographic changes after lung stereotactic body radiotherapy (SBRT).
  
  
  METHODS
  A participatory design process involving 6 radiation oncologists and 2 thoracic radiologists was used in the scale's design. Seventy-seven early-stage non-small-cell lung cancer patients who were treated with SBRT were included, and after treatment their serial computed tomography (CT) images were scored by 6 radiation oncologists. Gwet's First-order Agreement Coefficient (AC1) and a leave-one-out (LOO) analysis was used to assess interrater reliability and variability among raters, respectively.
  
  
  RESULTS
  The scale reports on 5 independent categories including "tumor in primary site," "tumor in involved lobe," "consolidation," "volume loss," and "ground-glass or interstitial changes." At each time point, each category is reported as "increased," "stable," "decreased," "obscured," or "not present," compared with the previous. The total number of rated images for the pilot ranged from 450 at 6 months to 84 at 48 months. The primary tumor site was scored as obscured in 38% to 40% of ratings from 12 months onward; 3% to 5% of primary tumors were scored as "increased." Consolidation, volume loss, and ground-glass or interstitial changes were increasingly marked as "stable" with time. At 24 months, AC1 was 0.28 (LOO, 0.22-0.42), 0.47 (LOO, 0.39-0.72), 0.45 (LOO, 0.42-0.50), 0.21 (LOO, 0.15-0.26), and 0.25 (LOO, 0.20-0.38) for the 5 categories listed, respectively.
  
  
  CONCLUSIONS
  In a population of clinicians, this scale could be implemented to characterize evolving lung changes after SBRT, and had fair to moderate interrater agreement. Obscured tumor site is a common challenge of follow-up CT imaging, and new imaging techniques should be explored. This scale provides a tool for communicating changes after SBRT.
authors.affiliation: Radiation Medicine Program, Department of Radiation Oncology, Princess Margaret Cancer Center, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Hamid
authors.initials: H
authors.lastname: Raziee
authors.affiliation: Radiation Medicine Program, Department of Radiation Oncology, Princess Margaret Cancer Center, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Hope
authors.affiliation: Radiation Medicine Program, Department of Radiation Oncology, Princess Margaret Cancer Center, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Salman
authors.initials: S
authors.lastname: Faruqi
authors.affiliation: Radiation Medicine Program, Department of Radiation Oncology, Princess Margaret Cancer Center, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Mei Ling
authors.initials: ML
authors.lastname: Yap
authors.affiliation: Department of Medical Imaging, University of Toronto, Women's College Hospital, Toronto, Ontario, Canada.
authors.forename: Heidi
authors.initials: H
authors.lastname: Roberts
authors.affiliation: Department of Medical Imaging, University of Toronto, Women's College Hospital, Toronto, Ontario, Canada.
authors.forename: Sonja
authors.initials: S
authors.lastname: Kandel
authors.affiliation: Department of Biostatistics, Princess Margaret Cancer Centre, Toronto, Ontario, Canada.
authors.forename: Lisa W
authors.initials: LW
authors.lastname: Le
authors.affiliation: Radiation Medicine Program, Department of Radiation Oncology, Princess Margaret Cancer Center, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Anthony
authors.initials: A
authors.lastname: Brade
authors.affiliation: Radiation Medicine Program, Department of Radiation Oncology, Princess Margaret Cancer Center, University of Toronto, Toronto, Ontario, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Cho
authors.affiliation: Radiation Medicine Program, Department of Radiation Oncology, Princess Margaret Cancer Center, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Alex
authors.initials: A
authors.lastname: Sun
authors.affiliation: Radiation Medicine Program, Department of Radiation Oncology, Princess Margaret Cancer Center, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Andrea
authors.initials: A
authors.lastname: Bezjak
authors.affiliation: Radiation Medicine Program, Department of Radiation Oncology, Princess Margaret Cancer Center, University of Toronto, Toronto, Ontario, Canada. Electronic address: meredith.giuliani@rmp.uhn.ca.
authors.forename: Meredith E
authors.initials: ME
authors.lastname: Giuliani
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D005260:Female; D005355:Fibrosis; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology / Q000528:radiation effects*; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011832:Radiation Injuries / Q000145:classification / Q000209:etiology; D016634:Radiosurgery / Q000009:adverse effects; D015203:Reproducibility of Results; D013997:Time Factors; D014057:Tomography, X-Ray Computed
keywords: Lung cancer; Postradiation lung fibrosis; Radiological changes; SBRT; Synoptic reporting