title: Clinical Significance of the Apparent Diffusion Coefficient Ratio in Prostate Cancer Treatment with Intensity-modulated Radiotherapy.
abstract: We aimed to investigate the correlation between biochemical recurrence (BCR) and the pretreatment apparent diffusion coefficient (ADC) ratio of tumor to normal prostate tissue in patients with prostate cancer who underwent intensity-modulated radiotherapy (IMRT).
  
  
  
  Retrospective analyses were performed for 101 patients diagnosed with localized prostate cancer who underwent IMRT at a dose of 70-78 Gy to the prostate gland and medial part of the seminal vesicles. Before treatment, all patients underwent magnetic resonance imaging including diffusion-weighted imaging of the prostate. BCR was defined as a rising prostate-specific antigen level (the Phoenix criterion).
  
  
  
  The median follow-up for all patients was 29 months, and BCR occurred in 10 patients (9.9%). ADC ratios and Gleason scores were significant independent prognostic factors of BCR by multivariate analysis.
  
  
  
  The pretreatment ADC ratio was an independent prognostic factor for BCR in patients with prostate cancer who underwent IMRT.
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Japan yhiroko@radonc.med.osaka-u.ac.jp.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Yamaguchi
authors.affiliation: Diagnostic and Interventional Radiology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hori
authors.affiliation: Carbon Ion Radiotherapy, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Suzuki
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Seo
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Isohashi
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yoshioka
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Iori
authors.initials: I
authors.lastname: Sumida
authors.affiliation: Urology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Motohide
authors.initials: M
authors.lastname: Uemura
authors.affiliation: Urology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Fujita
authors.affiliation: Urology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Nagahara
authors.affiliation: Urology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ujike
authors.affiliation: Urology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Atsunari
authors.initials: A
authors.lastname: Kawashima
authors.affiliation: Urology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Nonomura
authors.affiliation: Diagnostic and Interventional Radiology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Tomiyama
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ogawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D050397:Radiotherapy, Intensity-Modulated; D012189:Retrospective Studies
keywords: Diffusion-weighted imaging; apparent diffusion coefficient; biochemical recurrence; intensity-modulated radiotherapy; prostate cancer