title: Dummy run for a phase II multi-institute trial of chemoradiotherapy for unresectable pancreatic cancer: inter-observer variance in contour delineation.
abstract: The aim of this study was to examine the interobserver variance in delineating the contour of unresectable pancreatic cancer for chemoradiotherapy.
  
  
  METHODS
  CT images of two cases of unresectable pancreatic tumors (head and body cancer) were sent to eight radiation therapy facilities in a CD-ROM. Gross tumor volume (GTV) and planning target volume (PTV) were delineated using the radiotherapy treatment planning system (RTP) of the respective facilities. The mean and variance of the GTV and PTV of 11 plans by the eight facilities were analyzed.
  
  
  RESULTS
  The respective mean volumes of the GTV of pancreatic head and body cancer cases were 34.8 cm3 (SD, 30.4; median, 31.8; range, 13.5-122 cm3) and 73.4 cm3 (SD, 28.1; median, 67.9; range, 46.3-152 cm3). The ratios of the largest to the smallest contoured GTV were 9 and 3, respectively. The corresponding average volumes of PTV were 148 cm3 (SD, 84.3; median, 129; range, 69.6-363 cm3) and 240 cm3 (SD, 79.8; median, 227; range, 148-420 cm3). The ratios of the largest to the smallest contoured volume were 5 and 2.8 for PTV delineation, respectively.
  
  
  CONCLUSIONS
  Dummy run using CD-ROM is possible on a multi-institute scale but also disclosed interobserver variance. Unified protocol interpretation to reduce inter-observer variance is therefore essential for successful multi-institute clinical trials.
authors: Department of Radiology, National Hospital Organization Osaka National Hospital, Hoenzaka 2-1-14 Chuo-ku, Osaka city, Osaka, Japan. hideya10@hotmail.com
authors: Hideya
authors: H
authors: Yamazaki
authors: Kinji
authors: K
authors: Nishiyama
authors: Eiichi
authors: E
authors: Tanaka
authors: Keiichiro
authors: K
authors: Koiwai
authors: Naoto
authors: N
authors: Shikama
authors: Yoshinori
authors: Y
authors: Ito
authors: Satoko
authors: S
authors: Arahira
authors: Tetsuro
authors: T
authors: Tamamoto
authors: Toru
authors: T
authors: Shibata
authors: Yoshio
authors: Y
authors: Tamaki
authors: Takeshi
authors: T
authors: Kodaira
authors: Masahiko
authors: M
authors: Oguchi
mesh_terms: D003131:Combined Modality Therapy; D003198:Computer Simulation; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D006801:Humans; D008207:Lymphatic Metastasis; D009367:Neoplasm Staging; D015588:Observer Variation; D010190:Pancreatic Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000532:radiotherapy / Q000628:therapy*; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D000093542:Gemcitabine
chemical_list: D003841:Deoxycytidine; D000093542:Gemcitabine