title: Variability in clinical target volume delineation for intensity modulated radiation therapy in 3 challenging cervix cancer scenarios.
abstract: OBJECTIVE
  The purpose of this study was to assess variability in contouring the gross tumor volume (GTV) and clinical target volume (CTV) of 3 clinical cervix cancer cases by a cohort of international experts in the field in preparation for the development of an online teaching atlas.
  
  
  METHODS
  Twelve international experts participated. Three clinical scenarios: node positivity (PLN), retroverted uterus (RV), and parametrial invasion (PI) were used. Sagittal and axial magnetic resonance images of the clinical cases were downloaded to participants' treatment planning systems for contouring. The GTV/cervix/uterus/parametria/vagina and nodal CTV were contoured. Contour consensus was assessed for sensitivity/specificity using an expectation maximization algorithm called Simultaneous Truth and Performance Level Estimation and experts' overall agreement was summarized by kappa statistics.
  
  
  RESULTS
  Agreement for GTV in the 3 clinical cases was high (Simultaneous Truth and Performance Level Estimation sensitivity, 0.54-0.92; specificity, 0.97-0.98; and kappa measure for PLN, RV, and PI was 0.86, 0.76, and 0.42; P < .0001). Moderate to substantial agreement was seen for nodal CTV (kappa statistics for PLN, RV, and PI was 0.65, 0.58, and 0.62; P < .0001), uterus (kappa for PLN, RV, and PI was 0.45, 0.74, and 0.77; P < .0001), and parametria (kappa for PLN, RV, and PI was 0.49, 0.62, and 0.50; P < .0001). Contouring heterogeneity was greatest for the cervix (kappa measure for PLN, RV, and PI was 0.15, 0.4, and 0.24; P < .0001) and vagina (kappa for PLN, RV, and PI was 0.47, 0.36 and 0.46; P < .0001), reflecting difficulties in determining the interface between GTV and these tissues.
  
  
  CONCLUSIONS
  Kappa statistics of the different CTV components generally demonstrated moderate to substantial agreement among international experts in the field of gynecological radiation therapy. Further planning target volume margins accounting for organ motion and setup errors are a necessary addition to the CTV.
authors.affiliation: Liverpool Cancer Therapy Centre, Liverpool Hospital, Sydney, NSW, Australia.
authors.forename: Karen
authors.initials: K
authors.lastname: Lim
authors.affiliation: Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Beth
authors.initials: B
authors.lastname: Erickson
authors.affiliation: Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands.
authors.forename: Ina M
authors.initials: IM
authors.lastname: Jürgenliemk-Schulz
authors.affiliation: Department of Radiation Oncology, Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah.
authors.forename: David
authors.initials: D
authors.lastname: Gaffney
authors.affiliation: Department of Clinical Oncology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Carien L
authors.initials: CL
authors.lastname: Creutzberg
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts.
authors.forename: Akila
authors.initials: A
authors.lastname: Viswanathan
authors.affiliation: Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida.
authors.forename: Lorraine
authors.initials: L
authors.lastname: Portelance
authors.affiliation: Department of Radiation Oncology, Magee-Womens Hospital of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
authors.forename: Sushil
authors.initials: S
authors.lastname: Beriwal
authors.affiliation: Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida.
authors.forename: Aaron
authors.initials: A
authors.lastname: Wolfson
authors.affiliation: Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Walter
authors.initials: W
authors.lastname: Bosch
authors.affiliation: Department of Radiation Oncology, University of Alabama at Birmingham, Birmingham, Alabama.
authors.forename: Jennifer
authors.initials: J
authors.lastname: De Los Santos
authors.affiliation: Department of Radiation Medicine and Applied Sciences, University of California, San Diego, School of Medicine, La Jolla, California.
authors.forename: Catheryn
authors.initials: C
authors.lastname: Yashar
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital and Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts.
authors.forename: Anuja
authors.initials: A
authors.lastname: Jhingran
authors.affiliation: Department of Radiation Oncology, University of North Carolina, Chapel Hill, North Carolina.
authors.forename: Mahesh
authors.initials: M
authors.lastname: Varia
authors.affiliation: Department of Radiation Oncology, McGill University Health Center, Montreal, QC, Canada.
authors.forename: Issam
authors.initials: I
authors.lastname: El Naqa
authors.affiliation: Epworth Radiation Oncology, Epworth Healthcare, Melbourne, Victoria, Melbourne, VIC, Australia.
authors.forename: Bronwyn
authors.initials: B
authors.lastname: King
authors.affiliation: Radiation Medicine Program, Princess Margaret Hospital/Ontario Cancer Institute, University Health Network, Toronto, ON, Canada. Electronic address: Anthony.Fyles@rmp.uhn.on.ca.
authors.forename: Anthony
authors.initials: A
authors.lastname: Fyles
mesh_terms: D000328:Adult; D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000532:radiotherapy; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D058958:Organs at Risk; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods / Q000592:standards*; D047368:Tumor Burden; D002583:Uterine Cervical Neoplasms / Q000473:pathology* / Q000532:radiotherapy