title: A teaching intervention in a contouring dummy run improved target volume delineation in locally advanced non-small cell lung cancer: Reducing the interobserver variability in multicentre clinical studies.
abstract: BACKGROUND
  Interobserver variability in the definition of target volumes (TVs) is a well-known confounding factor in (multicentre) clinical studies employing radiotherapy. Therefore, detailed contouring guidelines are provided in the prospective randomised multicentre PET-Plan (NCT00697333) clinical trial protocol. This trial compares strictly FDG-PET-based TV delineation with conventional TV delineation in patients with locally advanced non-small cell lung cancer (NSCLC). Despite detailed contouring guidelines, their interpretation by different radiation oncologists can vary considerably, leading to undesirable discrepancies in TV delineation. Considering this, as part of the PET-Plan study quality assurance (QA), a contouring dummy run (DR) consisting of two phases was performed to analyse the interobserver variability before and after teaching.
  
  
  METHODS
  In the first phase of the DR (DR1), radiation oncologists from 14 study centres were asked to delineate TVs as defined by the study protocol (gross TV, GTV; and two clinical TVs, CTV-A and CTV-B) in a test patient. A teaching session was held at a study group meeting, including a discussion of the results focussing on discordances in comparison to the per-protocol solution. Subsequently, the second phase of the DR (DR2) was performed in order to evaluate the impact of teaching.
  
  
  RESULTS
  Teaching after DR1 resulted in a reduction of absolute TVs in DR2, as well as in better concordance of TVs. The Overall Kappa(κ) indices increased from 0.63 to 0.71 (GTV), 0.60 to 0.65 (CTV-A) and from 0.59 to 0.63 (CTV-B), demonstrating improvements in overall interobserver agreement.
  
  
  CONCLUSIONS
  Contouring DRs and study group meetings as part of QA in multicentre clinical trials help to identify misinterpretations of per-protocol TV delineation. Teaching the correct interpretation of protocol contouring guidelines leads to a reduction in interobserver variability and to more consistent contouring, which should consequently improve the validity of the overall study results.
authors: Department of Radiation Oncology, University Medical Center Freiburg, Robert-Koch-Str. 3, 79106, Freiburg, Germany, tanja.schimek-jasch@uniklinik-freiburg.de.
authors: Tanja
authors: T
authors: Schimek-Jasch
authors: Esther G C
authors: EG
authors: Troost
authors: Gerta
authors: G
authors: Rücker
authors: Vesna
authors: V
authors: Prokic
authors: Melanie
authors: M
authors: Avlar
authors: Viola
authors: V
authors: Duncker-Rohr
authors: Michael
authors: M
authors: Mix
authors: Christian
authors: C
authors: Doll
authors: Anca-Ligia
authors: AL
authors: Grosu
authors: Ursula
authors: U
authors: Nestle
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000000981:diagnostic imaging / Q000473:pathology* / Q000532:radiotherapy*; D002983:Clinical Competence; D005858:Germany; D006801:Humans; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000532:radiotherapy*; D008348:Manikins; D009426:Netherlands; D015588:Observer Variation; D018787:Radiation Oncology / Q000193:education*; D011877:Radionuclide Imaging; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D047368:Tumor Burden