title: Retroperitoneal Sarcoma Target Volume and Organ at Risk Contour Delineation Agreement Among NRG Sarcoma Radiation Oncologists.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the variability in target volume and organ at risk (OAR) contour delineation for retroperitoneal sarcoma (RPS) among 12 sarcoma radiation oncologists.
  
  
  METHODS
  Radiation planning computed tomography (CT) scans for 2 cases of RPS were distributed among 12 sarcoma radiation oncologists with instructions for contouring gross tumor volume (GTV), clinical target volume (CTV), high-risk CTV (HR CTV: area judged to be at high risk of resulting in positive margins after resection), and OARs: bowel bag, small bowel, colon, stomach, and duodenum. Analysis of contour agreement was performed using the simultaneous truth and performance level estimation (STAPLE) algorithm and kappa statistics.
  
  
  RESULTS
  Ten radiation oncologists contoured both RPS cases, 1 contoured only RPS1, and 1 contoured only RPS2 such that each case was contoured by 11 radiation oncologists. The first case (RPS 1) was a patient with a de-differentiated (DD) liposarcoma (LPS) with a predominant well-differentiated (WD) component, and the second case (RPS 2) was a patient with DD LPS made up almost entirely of a DD component. Contouring agreement for GTV and CTV contours was high. However, the agreement for HR CTVs was only moderate. For OARs, agreement for stomach, bowel bag, small bowel, and colon was high, but agreement for duodenum (distorted by tumor in one of these cases) was fair to moderate.
  
  
  CONCLUSIONS
  For preoperative treatment of RPS, sarcoma radiation oncologists contoured GTV, CTV, and most OARs with a high level of agreement. HR CTV contours were more variable. Further clarification of this volume with the help of sarcoma surgical oncologists is necessary to reach consensus. More attention to delineation of the duodenum is also needed.
authors.affiliation: Department of Radiation Oncology, Dana-Farber Cancer Institute, Brigham and Women's Hospital, Boston, Massachusetts. Electronic address: ebaldini@partners.org.
authors.forename: Elizabeth H
authors.initials: EH
authors.lastname: Baldini
authors.affiliation: Department of Radiation Oncology, Rush University Medical Center, Chicago, Illinois.
authors.forename: Ross A
authors.initials: RA
authors.lastname: Abrams
authors.affiliation: Department of Radiation Oncology, Washington University, St. Louis, Missouri.
authors.forename: Walter
authors.initials: W
authors.lastname: Bosch
authors.affiliation: Department of Radiation Oncology, Centre Hospitalier de l'Universite de Montreal, Montreal, Quebec, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Roberge
authors.affiliation: Department of Radiotherapy, Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Rick L M
authors.initials: RLM
authors.lastname: Haas
authors.affiliation: Department of Radiation Oncology, Princess Margaret Cancer Centre, Toronto, Ontario, Canada.
authors.forename: Charles N
authors.initials: CN
authors.lastname: Catton
authors.affiliation: Department of Radiation Oncology, University of Florida Medical Center, Jacksonville, Florida.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Indelicato
authors.affiliation: Department of Radiation Oncology, Washington University, St. Louis, Missouri.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Olsen
authors.affiliation: Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Curtiland
authors.initials: C
authors.lastname: Deville
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Yen-Lin
authors.initials: YL
authors.lastname: Chen
authors.affiliation: Translational Research Consortium, 21st Century Oncology, Scottsdale, Arizona.
authors.forename: Steven E
authors.initials: SE
authors.lastname: Finkelstein
authors.affiliation: Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Thomas F
authors.initials: TF
authors.lastname: DeLaney
authors.affiliation: Department of Radiation Oncology, Rush University Medical Center, Chicago, Illinois.
authors.forename: Dian
authors.initials: D
authors.lastname: Wang
mesh_terms: D000465:Algorithms; D003106:Colon / Q000000981:diagnostic imaging; D032921:Consensus; D004386:Duodenum / Q000000981:diagnostic imaging; D006801:Humans; D007421:Intestine, Small / Q000000981:diagnostic imaging; D008080:Liposarcoma / Q000000981:diagnostic imaging* / Q000473:pathology; D015588:Observer Variation; D058958:Organs at Risk / Q000000981:diagnostic imaging*; D010529:Peritoneal Cavity / Q000000981:diagnostic imaging; D017410:Practice Guidelines as Topic; D018787:Radiation Oncology; D011880:Radiotherapy Planning, Computer-Assisted; D012186:Retroperitoneal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D012509:Sarcoma / Q000000981:diagnostic imaging / Q000473:pathology; D013270:Stomach / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden