Variation of clinical target volume definition among Japanese radiation oncologists in external beam radiotherapy for prostate cancer.
BACKGROUND
We investigated the interobserver variation in the prostate target volume and the trend toward the use of diagnostic computed tomography (CT) or magnetic resonance (MR) images for treatment planning.


METHODS
Twenty-five radiation oncologists were asked to draw the external contour of the prostate on CT images (0.3 cm spacing) of a patient with localized prostate cancer. They also answered a questionnaire regarding the use of diagnostic CT or MR images for the contouring.


RESULTS
Of the 25 physicians, 28% rarely or never referred to the diagnostic CT images. In contrast, the physicians tended to refer to the MR images more frequently. Approximately 50% of the physicians believed in the usefulness of contrast-enhanced images for the delineation of the prostate. As for the variation of the prostate contouring, the median craniocaudal prostate length was 36 mm (range, 21-54 mm), and the median prostate volume was 43.5 cm(3) (range, 23.8-98.3 cm(3)). The interobserver variability was not significant in the duration as a radiation oncologist, the board certification status as radiation oncologists, and the number of treatment plans developed for prostate cancer during the last 1 year.


CONCLUSIONS
A wide variety of the definitions of the prostate was found among Japanese radiation oncologists.
Nakamura
Katsumasa
K
Department of Radiology, School of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan. nakam@fukuoka-u.ac.jp
Shioyama
Yoshiyuki
Y
Tokumaru
Sunao
S
Hayashi
Nobuyuki
N
Oya
Natsuo
N
Hiraki
Yoshiyuki
Y
Kusuhara
Kazuo
K
Toita
Takafumi
T
Suefuji
Hiroaki
H
Hayabuchi
Naofumi
N
Terashima
Hiromi
H
Makino
Masaoki
M
Jingu
Kenichi
K
D000368:Aged; D002568:Certification; D006801:Humans; D007564:Japan; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D011871:Radiology; D011878:Radiotherapy / Q000379:methods; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D013044:Specialty Boards; D011795:Surveys and Questionnaires; D014057:Tomography, X-Ray Computed; D000078329:Workforce