Abstract
The standard endoscopic treatment of bulbar urethral strictures prior to the development of the direct vision balloon dilator was dilation with sounds or filiforms and followers or direct vision internal urethrotomy (DVIU). Although older literature implied reasonable success, a subsequent study in 2010 indicated that the DVIU success rate was only 8% for initial treatment and approximately 0% when performed repeatedly. 1 Factors that can explain major differences in success rates include how success is defined. In 2011, I described the first use of the direct vision balloon dilator. 2 It was originally made available by Cook Urological (4 cm 30Fr balloon) and then marketed by Boston Scientific as the “Uromax.” Optilume adds a paclitaxel drug coating to the balloon dilator. The concept is that after the stricture is dilated or incised, “micro-fissures” are created, allowing drug absorption within the urethra, inhibiting wound contraction, and reducing or delaying stricture recurrence.
This updated ROBUST III study article reports that Optilume provides superior outcomes compared with a control group that received any “standard endoscopic treatment,” which was left up to the discretion of the surgeon. A much better control group would have been direct vision balloon dilation without the drug coating. In the ROBUST III trials, no conclusions can be made regarding the effectiveness of paclitaxel compared to balloon dilation without the added drug coating.
The appeal of Optilume compared to urethroplasty is that it is a less invasive, short procedure that is not associated with a prolonged recovery and does not require any subspecialty expertise. If the outcomes were similar, anastomotic urethroplasty would become obsolete. Anatomical success is a primary outcome measure in many urethral stricture treatment publications where cystoscopy (urethroscopy) is performed months after treatment to assess patency under direct vision. 3 Anastomotic urethroplasty can be associated with up to a 98+% long-term cure rate. 4,5
In this study, the Optilume anatomical success definition included the ability to pass a 16Fr cystoscope or a 14Fr catheter. The ability to pass a catheter does not clearly determine if the urethra is widely patent or if there is a “soft stricture” recurrence amenable to catheter dilation without significant resistance or force. Ideally, the follow-up protocol would not have allowed the ability to catheterize to be a substitute for cystoscopy, even if applicable to a small minority of the patients. The published 1year ROBUST III results indicated a 25% early recurrence rate, 6 indicating a cure rate of 75% at best if and only if all of the patients who did not have an early failure remained without subsequent recurrent stricture recurrence. With anastomotic urethroplasty, early anatomical success is highly associated with long-term success. 5 However, with the use of a drug coating that may delay recurrence, repeat anatomical assessment becomes especially valuable.
The focus of this study was the 3-year functional outcomes after Optilume. It is encouraging that many patients achieved sustained symptomatic improvement. However, the IPSS is an inadequate stand-alone tool to screen for urethral stricture recurrence. 7 The progressive decline from posttreatment baseline in mean maximal flow rate to 10.6 mL/s at 3 years and concurrent increase in IPSS suggest unrecognized lower urinary obstruction in a high proportion of patients, which could have been easily evaluated with the inclusion of cystoscopy into the study protocol beyond 6 months. The major outcome measure that appears to be driving the promotion and use of this product is a high rate of freedom from reintervention after Optilume. Freedom from retreatment is valuable information, but it should be emphasized that this does not prove that the 71% that did not require retreatment all had durable wide urethral patency. Many men who undergo treatment for recurrent strictures 3+ years after prior endoscopic treatment likely had recurrence long before pursuing subsequent treatment. Some present in retention, not realizing their bladders were getting progressively damaged until there was decompensation. 8
The authors are to be commended for their innovative efforts to develop a dilation method that adds a drug coating to the direct vision balloon dilator and report follow-up for this novel treatment beyond the short-term. Optilume is being promoted as a breakthrough, and the addition of paclitaxel may very well represent a major advance over non-drug-coated balloon dilation. I hope so. However, additional data with studies that address limitations of the current study design are needed before the true effectiveness of the paclitaxel drug coating is established in curing stricture disease or delaying recurrence in the long term.