title: Morphological analysis of the effects of intraoperative transrectal compression of the prostate during high-intensity focused ultrasound for localized prostate cancer.
abstract: OBJECTIVE
  To evaluate the effects of transrectal compression of the prostate for intra-operative prostatic swelling and intraprostatic point shift during high-intensity focused ultrasound treatment of localized prostate cancer.
  
  
  METHODS
  Patients treated with whole-gland high-intensity focused ultrasound as primary monotherapy for localized prostate cancer were enrolled in the study. Using the standard and compression method, the volumes of degassed water in the balloon covering the high-intensity focused ultrasound probe were 50 mL and 80-160 mL, respectively. To identify prostatic swelling and shift during high-intensity focused ultrasound and the volume occupied by the non-enhanced area, three-dimensional prostate models were reconstructed using ultrasound and contrast-enhanced magnetic resonance imaging.
  
  
  RESULTS
  In comparison with the standard (n = 40) and compression (n = 48) methods, intraoperative increase in the prostate volume (21% vs 5.3%; P = 0.044), intraprostatic point shift (4 mm vs 2 mm, P = 0.040 in the transition zone; 3 mm vs 0 mm; P = 0.001 in the peripheral zone) and the volume occupied by the non-enhanced area (89% vs 96%; P = 0.001) were significantly suppressed. The biochemical disease-free survival rate in patients treated using the compression method was significantly improved relative to the standard method (92.6% vs 76.5%; P = 0.038). Regarding complications, there was no significant difference in the rate of urethral stricture (P = 0.9), urinary tract infection (P = 0.9), incontinence (P = 0.3), erectile dysfunction (P = 0.9) or recto-urethral fistula between the patients treated using the standard and compression methods.
  
  
  CONCLUSIONS
  Intraoperative transrectal compression suppresses intraoperative increase in the prostate volume and intraprostatic point shift during high-intensity focused ultrasound, having the potential to achieve precise whole-gland and lesion-targeted focal therapy.
authors: Department of Urology, Tokai University Hachioji Hospital, Hachioji, Tokyo, Japan.
authors: Sunao
authors: S
authors: Shoji
authors: Department of Radiology, Tokai University Hachioji Hospital, Hachioji, Tokyo, Japan.
authors: Akio
authors: A
authors: Hashimoto
authors: Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors: Masahiko
authors: M
authors: Nakamoto
authors: Department of Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors: Norio
authors: N
authors: Fukuda
authors: Department of Radiology, Tokai University Hachioji Hospital, Hachioji, Tokyo, Japan.
authors: Hiroshi
authors: H
authors: Fujikawa
authors: Department of Radiology, Tokai University Hachioji Hospital, Hachioji, Tokyo, Japan.
authors: Kazuyuki
authors: K
authors: Endo
authors: Department of Urology, Tokai University Hachioji Hospital, Hachioji, Tokyo, Japan.
authors: Tetsuro
authors: T
authors: Tomonaga
authors: Department of Urology, Tokai University Hachioji Hospital, Hachioji, Tokyo, Japan.
authors: Mayura
authors: M
authors: Nakano
authors: Department of Urology, Tokai University School of Medicine, Isehara, Kanagawa, Japan.
authors: Toshiro
authors: T
authors: Terachi
authors: Department of Urology, Tokai University Hachioji Hospital, Hachioji, Tokyo, Japan.
authors: Toyoaki
authors: T
authors: Uchida
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D018572:Disease-Free Survival; D057086:High-Intensity Focused Ultrasound Ablation / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011312:Pressure; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D017430:Prostate-Specific Antigen
keywords: high-intensity focused ultrasound; magnetic resonance imaging; prostate cancer; transrectal compression; transrectal ultrasound