title: Development of bladder outlet obstruction after a single treatment of prostate cancer with high-intensity focused ultrasound: experience with 226 patients.
abstract: OBJECTIVE
  To investigate the occurrence of bladder outlet obstruction (BOO) after high-intensity focused ultrasound (HIFU) therapy of prostate cancer, the need for secondary transurethral interventions for BOO, and the benefit of transurethral resection of the prostate (TURP) before HIFU.
  
  
  METHODS
  After a single HIFU treatment between 2002 and 2007, 226 consecutive patients were examined and followed at least 2 years. The Ablatherm Maxis and the Integrated Imaging devices were used. The sites of BOO were recorded.
  
  
  RESULTS
  Median follow-up after HIFU was 52 months (range 24-80 mos). BOO developed in 58 (25.66%) patients. Repeated BOO episodes were observed in 27 (11.94%), three to seven episodes in 13 (5.75%) patients. Patients with repeated BOO were older than patients with singular BOO (71.75 ± 4.97 vs 68.18 ± 5.03; P = 0.024). In primary BOO, multiple sites of obstruction were more often involved than in repeated BOO (25/58 vs 8/27). Conversely, isolated bladder neck stenosis was predominantly found in patients with ≥two episodes of BOO. The rate of primary BOO was significantly different between patients who had undergone TURP the same day as HIFU or within 2 days of HIFU (33/96; 34.38%) and patients with TURP more than 1 month (16/89; 17.98%) before HIFU (P = 0.032). BOO occurred in 21.95% (9/41) of the patients who were treated with HIFU only.
  
  
  CONCLUSIONS
  BOO after HIFU is common, particularly affecting the bladder neck. The risk of repeated BOO is associated with age. A longer interval between TURP and HIFU (>1 month) might reduce the risk for the development of BOO.
authors.affiliation: Department of Urology, Asklepios Hospital Barmbek, Hamburg, Germany. c.netsch@asklepios.com
authors.forename: Christopher
authors.initials: C
authors.lastname: Netsch
authors.forename: Dietrich
authors.initials: D
authors.lastname: Pfeiffer
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Gross
mesh_terms: D000368:Aged; D006801:Humans; D008297:Male; D011471:Prostatic Neoplasms / Q000000981:diagnostic imaging*; D020728:Transurethral Resection of Prostate / Q000009:adverse effects; D014463:Ultrasonography; D036761:Ultrasound, High-Intensity Focused, Transrectal / Q000009:adverse effects*; D001748:Urinary Bladder Neck Obstruction / Q000209:etiology*