Retroperitoneal Sarcoma Target Volume and Organ at Risk Contour Delineation Agreement Among NRG Sarcoma Radiation Oncologists

• Published in: International journal of radiation oncology, biology, physics Vol. 92; no. 5; pp. 1053 - 1059
• Main Authors: Baldini, Elizabeth H., MD, MPH, Abrams, Ross A., MD, Bosch, Walter, DSc, Roberge, David, MD, Haas, Rick L.M., MD, PhD, Catton, Charles N., MD, Indelicato, Daniel J., MD, Olsen, Jeffrey R., MD, Deville, Curtiland, MD, Chen, Yen-Lin, MD, Finkelstein, Steven E., MD, DeLaney, Thomas F., MD, PhD, Wang, Dian, MD, PhD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-08-2015
• Subjects: Algorithms; CAT SCANNING; Colon - diagnostic imaging; Consensus; Duodenum - diagnostic imaging; HAZARDS; Hematology, Oncology and Palliative Medicine; Humans; Intestine, Small - diagnostic imaging; LARGE INTESTINE; Liposarcoma - diagnostic imaging; Liposarcoma - pathology; MEDICAL PERSONNEL; Observer Variation; Organs at Risk - diagnostic imaging; PATIENTS; Peritoneal Cavity - diagnostic imaging; PLANNING; Practice Guidelines as Topic; Radiation Oncology; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; Radiotherapy Planning, Computer-Assisted; Retroperitoneal Neoplasms - diagnostic imaging; Retroperitoneal Neoplasms - pathology; Sarcoma - diagnostic imaging; Sarcoma - pathology; SARCOMAS; SMALL INTESTINE; STATISTICS; STOMACH; Stomach - diagnostic imaging; SURGERY; Tomography, X-Ray Computed; Tumor Burden
• ISSN: 0360-3016; 1879-355X
• DOI: 10.1016/j.ijrobp.2015.04.039

Purpose 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 and Materials 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.