Effect of onabotulinum toxin type a intraprostatic injection on the outcome of Benign Prostatic Hyperplasia patients refractory to medical therapy: A 2-year follow-up study.

OBJECTIVES: To determine the outcome of Benign Prostatic Hyperplasia patients refractory to standard medical therapy and with significant comorbidities submitted to intraprostatic injection of onabotulinum toxin A.

METHODS: Thirty-seven patients with symptomatic Benign Prostatic Hyperplasia refractory to medical therapy who were poor candidates for surgical treatment were enrolled. All patients voided spontaneously. They received one single transrectal application of 200 U of onabotulinum toxin A. All medical therapy was discontinued. The primary objective was to evaluate the percentage of patients that were still accepting to postpone the surgery at 2 years. As secondary objectives the variation of International Prostate Symptom Score and maximum urinary flow rate were also investigated.

RESULTS: From the initial cohort, 2 patients developed severe cognitive impairment and eight patients abandoned the study and opted for surgery, due to acute urinary retention or lack of symptomatic improvement. Four patients were lost to follow-up. In the non-failure cohort, baseline International Prostate Symptom Score and Quality of Life and Postvoid Residual Volume decreased significantly and Maximum urinary flow rate increased significantly after injection. Prostate-Specific Antigen values showed no statistically significant variation. We did not find any statistically significant differences between the 2 cohorts regarding basal parameters.

CONCLUSIONS: Intraprostatic onabotulinum toxin A injection can be an option for treatment of Benign Prostatic Hyperplasia/Lower Urinary Tract Symptoms refractory to medical treatment in poor surgical candidates, preventing surgery in at least two thirds of the patients. Side effects are limited to acute prostatitis.