Bladder outlet obstruction (BOO) in men with castration-resistant prostate cancer




  • To evaluate the frequency of bladder outlet obstruction (BOO) and detrusor overactivity (DO) in patients with castration-resistant prostate cancer (CRPC) and lower urinary tract symptoms (LUTS).

Patients and Methods

  • Our prospective urodynamics database was queried.
  • Inclusion criteria were CRPC and an International Prostate Symptom Score (IPSS) ≥ 20.
  • Exclusion criteria were previous local therapy to the prostate gland, known urethral stricture disease, and a neurological component of LUTS.
  • Twenty-one patients were identified.
  • Urodynamic findings were analysed and compared with those of a matched cohort of 42 patients with benign prostatic enlargement (BPE).


  • The median age of patients in the CRPC group was 74 years, and the median prostate-specific antigen (PSA) level at the time of the urodynamic study was 90 ng/mL.
  • According to the BOO index, three patients (14%) were obstructed, three were equivocally obstructed (14%) and 15 were unobstructed.
  • DO was seen in 12 patients (57%).
  • Compared with the BPE group, patients with CRPC had lower cystometric bladder capacities (P = 0.003), were less likely to have BOO (14 vs 43%, P = 0.009) and more likely to have DO (57 vs 29%, P = 0.028).


  • This study generates the hypothesis that only a minority of CRPC patients with LUTS have BOO, and that more than half of patients have DO.
  • LUTS in CRPC may therefore be seldom attributable to BOO, but are, at least in part, related to DO and reduced cystometric capacity.
  • A urodynamic investigation may be necessary before palliative transurethral resection of the prostate to select appropriate candidates.
  • Larger prospective studies are needed to confirm our findings.