Bladder botulinum toxin A injection can benefit patients with radiation and chemical cystitis

To investigate the potential utility of botulinum toxin A (BoNT-A) bladder injections in patients with radiation cystitis and bacillus Calmette-Guérin (BCG)-induced chemical cystitis.

In all, six patients with refractory radiation cystitis were treated with 200 U bladder BoNT-A injections and two patients with refractory cystitis after intravesical BCG therapy were treated with 100 U bladder BoNT-A injections. All the patients were refractory to anticholinergic agents. Under sedation or local anaesthesia, BoNT-A was injected through a cystoscope into 20 sites submucosally in the trigone and floor of the bladder.

There were no side-effects or retention after BoNT-A injection. In five of the six patients with radiation cystitis there was a moderate to significant improvement; the mean (sd) bladder capacity increased from 105 (25) mL to 250 (35) mL and the urinary frequency decreased from 14 (2) to 11 (1) episodes per day. In the two patients with BCG cystitis both reported significant symptomatic improvement; the mean (sd) bladder capacity increased from 110 (23) to 230 (23) mL, the urinary frequency decreased from 16 (1) to 12 (1) episodes per day, and using a 10-point visual analogue pain scoring system, the perceived pain score decreased from 8 to 2. Microscopically, the bladder tissue at 1 month after BCG injection showed marked acute and chronic inflammation with eosinophilic infiltration and focal granulomatous formation. At 2 months after BoNT-A injection, there was only a mild degree of chronic inflammation with few eosinophils.

These preliminary results suggest that BoNT-A injected into the bladder is a promising treatment for patients with refractory radiation and BCG cystitis.