title: Definitive 3D-CRT for clinically localized prostate cancer: modifications of the clinical target volume following a prostate MRI and the clinical benefits.
abstract: OBJECTIVE
  To evaluate the modifications of the tumor stage and clinical target volume following a prostate magnetic resonance imaging (MRI) to evaluate the tumor (T) staging, and the clinical benefits for prostate cancer.
  
  
  METHODS
  A total of 410 patients with newly diagnosed and clinically localized prostate cancer were retrospectively analyzed. The patients were treated with definitive three-dimensional conformal radiotherapy (3D-CRT). In all of the patients, digital rectal examination, transrectal ultrasound, prostate biopsy and computed tomography were performed to evaluate the clinical stage. Of the 410 patients, 189 patients had undergone a prostate MRI study to evaluate the T staging, and 221 patients had not.
  
  
  RESULTS
  Modification of the T stage after the prostate MRI was seen in 39 (25%) of the 157 evaluable patients, and a modification of the risk group was made in 14 (9%) patients. Eventually, a modification of the CTV in 3D-CRT planning was made in 13 (8%) patients, and 10 of these had extracapsular disease. Most of the other modifications of the T staging were associated with intracapsular lesions of prostate cancer which did not change the CTV. There were no significant differences in the biological relapse-free survival between the patients with and without a prostate MRI study.
  
  
  CONCLUSIONS
  Modification of the CTV were recognized in only 8% of the patients, most of whom had extracapsular disease, although that of the T stage was seen in approximately one-quarter of the patients. Prostate MRI should only be selected for patients with a high probability of extracapsular involvement.
authors.affiliation: Department of Radiology, Kitakyushu General Hospital, Kitakyushu, Japan.
authors.forename: Shinsaku
authors.initials: S
authors.lastname: Yamaguchi
authors.affiliation: Department of Radiology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555 Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Ohguri
authors.affiliation: Department of Radiology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555 Japan.
authors.forename: Masami
authors.initials: M
authors.lastname: Fujii
authors.affiliation: Department of Radiology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555 Japan.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Yahara
authors.affiliation: Department of Radiology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555 Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Hayashida
authors.affiliation: Department of Urology, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Fujimoto
authors.affiliation: Department of Radiology, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu, 807-8555 Japan.
authors.forename: Yukunori
authors.initials: Y
authors.lastname: Korogi
keywords: Clinical target volume; Magnetic resonance imaging; Prostate cancer; Three-dimensional conformal radiotherapy; Tumor staging