RESUMEN
The injection of Botulinum toxin type A (BoNT/A) into the prostate is a minimally invasive alternative treatment for lower urinary tract symptoms. To summarize the action mechanisms of BoNT/A on experimental animals and to analyze its effectiveness according to published clinical studies, we located 24 papers on the treatment of HBP with BoNT/A. The doses applied ranged from 100 (OnabotA) to 600 U (OnabotA and AbobotA). The IPSS score presented a mean post-treatment reduction, for all series, of 10.8 + 2.66 points. Other significant results included the overall mean reduction in QoL score of 2.1 ± 0.62 points, and the pre and post-treatment differences in prostate volume (22.43 ± 20.2 cm(3)), post-voiding residue (76.77 + 51.72 cm(3)) and PSA (1.15 + 0.93 ng/ml). However, only two clinical trials were on sufficient quality to be selected for meta-analysis, and it was observed that the difference of the means, pre- and post-treatment of maximum flow, prostate volume, IPSS and PSA were not statistically significant (P = 0.18). Neither was there any statistically significant difference between pre- and post-treatment post-voiding residue (P = 0.65). In conclusion, BoNT/A alleviates lower urinary tract symptoms due to HBP, but different studies present considerable variations regarding the dose administered, inclusion criteria and follow-up time, as well as poorly defined retreatment, losses to follow up and, above all, a high degree of variability in the communication of results (with large standard deviations). In consequence, further clinical trials are needed.