Dummy run for a phase II multi-institute trial of chemoradiotherapy for unresectable pancreatic cancer: inter-observer variance in contour delineation.
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.
Yamazaki
Hideya
H
Department of Radiology, National Hospital Organization Osaka National Hospital, Hoenzaka 2-1-14 Chuo-ku, Osaka city, Osaka, Japan. hideya10@hotmail.com
Nishiyama
Kinji
K
Tanaka
Eiichi
E
Koiwai
Keiichiro
K
Shikama
Naoto
N
Ito
Yoshinori
Y
Arahira
Satoko
S
Tamamoto
Tetsuro
T
Shibata
Toru
T
Tamaki
Yoshio
Y
Kodaira
Takeshi
T
Oguchi
Masahiko
M
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
D003841:Deoxycytidine; D000093542:Gemcitabine