title: Inter-tester reproducibility of tumour change in small cell lung cancer patients undergoing chemoradiotherapy.
abstract: BACKGROUND
  Tumour volume change during delivery of chemoradiotherapy is observed in small cell lung cancer (SCLC) patients. In this study, we have compared tumour volume and anatomical changes, e.g. atelectasis or pleural effusions determined by three different methods.
  
  
  METHODS
  A total of 37 SCLC patients undergoing thoracic radiotherapy during 2010-2011 were included. The patients were treated based on a daily three-dimensional (3D) cone beam computed tomography (CBCT) bony anatomy registration. The CBCT scans were retrospectively reviewed visually by a radiation therapist (Visual-RTT) in order to register tumour volume changes. Furthermore, the tumour volume changes were obtained by either deformable image registration (DIR) or delineation by a radiation oncologist (RO). Kappa (κ) statistics and paired t-tests were used for evaluation of the inter-tester agreement.
  
  
  RESULTS
  The tumour volume change between the Visual-RTT, the DIR and the RO assessments obtained 84-97% agreement (κ = 0.68-0.95). Furthermore, there was no statistically significant difference between the tumour change assessment of the RO (mean 13.6 ml) and the DIR (mean 14.5 ml), p = 0.59. Tumour shrinkage was observed in 15 (41%) patients and anatomical changes in seven (19%) patients.
  
  
  CONCLUSIONS
  The inter-tester reproducibility of tumour volume change between the three methods is excellent. Visual-RTT on-line inspection may be used to determine tumour shrinkage and anatomical changes as atelectasis or pleural effusions during the radiotherapy course by use of daily CBCT scans.
authors.affiliation: Department of Oncology, Aarhus University Hospital , Aarhus , Denmark.
authors.forename: Mai-Britt Bjørklund
authors.initials: MB
authors.lastname: Ellegaard
authors.forename: Marianne Marquard
authors.initials: MM
authors.lastname: Knap
authors.forename: Lone
authors.initials: L
authors.lastname: Hoffmann
mesh_terms: D000465:Algorithms; D059248:Chemoradiotherapy; D054893:Cone-Beam Computed Tomography; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy; D009367:Neoplasm Staging; D011379:Prognosis; D011856:Radiographic Image Enhancement; D011880:Radiotherapy Planning, Computer-Assisted; D061089:Radiotherapy, Image-Guided; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies; D055752:Small Cell Lung Carcinoma / Q000000981:diagnostic imaging / Q000473:pathology* / Q000628:therapy; D047368:Tumor Burden