Treatment of refractory category III nonbacterial chronic prostatitis/chronic pelvic pain syndrome with intraprostatic injection of onabotulinumtoxinA: a prospective controlled study

Abstract

Introduction: To evaluate the efficacy and safety of intraprostatic injections of onabotulinumtoxinA (onaBoNT-A) to treat refractory chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS).

Materials and methods: Prospective two-group controlled study. Treatment group included adult men with refractory category-III nonbacterial CP/CPPS who underwent transurethral intraprostatic injections of onaBoNT-A (200 U). Control group included comparable patients who underwent cystoscopy only. Primary outcome was the proportion of 6-point responders (≥ 6 points reduction of total score of National Institutes of Health-Chronic Prostatitis Symptom Index [NIH-CPSI]), at 3 months. Secondary outcomes included proportions of quality of life (QoL) responders (≤ 2 points in QoL domain), and global response assessment (GRA) responders (patients reporting moderately improved, or markedly improved), at 3 months. Other outcomes comprised changes from baseline NIH-CPSI scores, visual analog scale (VAS) sub-score of pain domain, PSA, prostate volume, post-void residual urine, and maximum flow rate. Significance was set at p < 0.05.

Results: Treatment group included 43 patients with mean age (SD) of 38.8 (7.3) years and mean duration of symptoms of 7.0 (2.9) years. At 3 months, the proportions of responders (NIH-CPSI 6-point, QoL, and GRA) were 72.1%, 69.8%, and 72.1%; which gradually declined to 37.2%, 25.7% and 27.9%, respectively, at 12 months. The baseline NIH-CPSI total score demonstrated -68.2% reduction at 3 months (-20.1 points; p < 0.0001); which gradually waned to -19% reduction (-5.6 points; p < 0.0001) at 12 months. Baseline VAS showed -79%, and -27.4% reductions at 3 and 12 months, respectively (p < 0.0001, each). None of control men has been 6-point, QoL nor GRA responder and none has demonstrated significant NIH-CPSI scores changes from baseline (p > 0.05, each). Compared to control, mean NIH-CPSI total scores of treated men at 1 and 3 months were significantly different (p < 0.001, each).

Conclusion: OnaBoNT-A intraprostatic injections appeared to be effective and safe to ameliorate symptoms of refractory nonbacterial CP/CPPS; with pain most improved. The improvements gradually dwindled at 9-12 months.