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

Objective. 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 -blocker and 5--reductase inhibitor therapy. Material and methods. 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. Results. 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. Conclusions. 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.