Sustained beneficial effects of intraprostatic botulinum toxin type A on lower urinary tract symptoms and quality of life in men with benign prostatic hyperplasia

OBJECTIVE To present a comprehensive experience with intraprostatic botulinum toxin-type A (BoNT-A) injection in men with symptomatic benign prostatic hyperplasia (BPH) and to assess the efficacy on lower urinary tract symptoms (LUTS) and quality of life (QoL). PATIENTS AND METHODS In all, 41 men (mean age 69.1 years, SD 7.1 ) with an International Prostate Symptom Score of >= 8, peak flow rate of < 12 mL/s, and who were refractory to medical treatment were injected with BoNT-A (Botox (R), Allergan, Inc., CA, USA) at 100 U (21 men, for prostate volume < 30 mL) or 200 U (20, for prostate volume > 30 mL) into the prostate transperineally under transrectal ultrasonography guidance. Study exclusion criteria were confirmed or suspected malignancy, previous pelvic surgery or trauma and previous invasive treatment for BPH. The clinical effects were evaluated at baseline and at 1, 3 and 6 months after treatment. RESULTS There were no significant local or systemic side-effects in any men. LUTS and QoL indices improved by > 30% in 31 of the 41 men (76%), and four of five men with urinary retention for > 1 month could void spontaneously at 1 week to 1 month after the BoNT-A injection. In 12 of 41 men (29%) there was no change in prostate volume, yet seven of these men still had a > 30% improvement in maximum flow rate, LUTS and QoL. The efficacy was sustained at 12 months. CONCLUSION BoNT-A injected into the prostate is safe and effective for men with symptomatic BPH. The mechanisms of relief of symptoms might not depend totally on the volume shrinkage; the inhibitory effect on the smooth muscle tone and aberrant sensory function might also be important.