Transurethral Intraprostatic Botulinum Toxin-a Injection in Patients with Benign Prostatic Hyperplasia: A Case Series and Literature Review

Background: We aimed to assess the efficacy of Intraprostatic Onabotulinumtoxin-A (BTA) on the International Prostate Symptom Score (IPSS) and other objective measures of patients with Benign Prostatic Hyperplasia (BPH). Methods: Fifteen patients were included in this study. The drug (BTA; 150 IU) was reconstituted in 20 mL of 0.9% saline before administration to the patients. After providing urethral anesthesia, 20 intraurethral injections were made to lateral lobes of the prostate, 10 injections in each lobe. Follow-up visits were planned 3 and 12 months after the intervention. Pre- and post-interventional IPSS, Prostate-Specific Antigen (PSA), Prostate Volume (PV), Post-Void Residue (PVR), and maximum urinary flow rate (Qmax) compared via paired t-test. Finally, we reviewed the Pubmed database to provide a more precise conclusion. Results: The Mean±SD age of patients was 69±8.24 years, and the mean IPSS score decreased significantly from 24.3±3.3 to 14.6±3.7 (p<0.001) and 16.86±3.06 (p<0.009) on the 3rd and 12th months, respectively. The Mean±SD PSA, PVR, Qmax, and PV were 3.26±1.38, 82.33±35.55, 8.56±1.76, and 47.86±8.93, respectively at baseline. These factors significantly improved to 2.72±1.33 (P<0.000), 71.33±30.55 (p<0.000), 9.5±1.33 (p<0.011), and 42.86± 6.04 (p<0.000), respectively, on the 12th month follow-up. Conclusion: Although the overall results support the efficacy of BTA for BPH, the best route of administration, the most effective dose, the optimal number, and the volume of injections need further investigations. The probable placebo effect and underlying medical conditions (e.g., insulin resistance) should be considered as the confounding factors.