Therapeutic effects of add-on botulinum toxin A on patients with large benign prostatic hyperplasia and unsatisfactory response to combined medical therapy

Abstract

Botulinum toxin A (BoNT-A) injections into the prostate have been reported to be effective and durable in the treatment of small benign prostatic hyperplasia (BPH). This study evaluated the effectiveness of BoNT-A in patients with large BPH with an unsatisfactory response to combined alpha-blocker and 5-alpha-reductase inhibitor therapy. Sixty patients with BPH and total prostate volume (TPV) of > 60 ml with unsatisfactory response to combination medical therapy were randomly assigned to receive add-on intraprostatic BoNT-A injection (n=30) or continued medical therapy (control group). Patients in the treatment group received 200-600 U of Botox injected into the prostate. Outcome parameters including International Prostate Symptom Score (IPSS), quality of life index (QoL-I), TPV, maximum flow rate (Q(max)) and postvoid residual (PVR) were compared between treatment and control groups at baseline, 6 months and 12 months. Significant decreases in IPSS, QoL-I and TPV, and increase in Q(max) were observed at 6 months and remained stable at 12 months in the treatment group. Improvements in IPSS and QoL-I were also observed at 6 months and a decrease in TPV at 12 months was noted in the control group. However, no significant changes in any parameters except for QoL-I at 6 and 12 months were noted between the treatment and control groups. Acute urinary retention developed in three patients receiving BoNT-A treatment. Three BoNT-A and two medical treatment patients converted to transurethral surgery at the end of study. This study shows that add-on prostatic BoNT-A medical treatment can reduce prostate volume and improve lower urinary tract symptom score and QoL-I within 6 months in the treatment of large BPH. However, the therapeutic effect at 12 months was similar to combination medical treatment.