Abstract
Background
The Optilume® drug-coated balloon is a urethral dilation balloon with a paclitaxel coating that combines mechanical dilation for immediate symptomatic relief with local drug delivery to maintain urethral patency. The ROBUST III trial concludes that Optilume is safe and superior to standard direct vision internal urethrotomy/dilation for the treatment of recurrent anterior urethral strictures <3 cm in length. However, there have been limited studies to show efficacy in the treatment of urethral stricture in the setting of post-radiation patients. This study aimed to clarify the safety and early efficacy of Optilume balloon dilation for urethral strictures in post-radiation patients.
Methods
All patients undergoing Optilume balloon dilation with at least 3 months of follow-up were evaluated over 27 months in a retrospective multi-institutional setting. Thirty patients who received pelvic radiation and subsequently developed symptomatic urethral strictures were selected from a total of 246 patients identified with symptomatic urethral strictures. Success was defined as the absence of recurrence of original presenting symptoms, no need for intermittent self-dilation, and no requirement for surgical intervention within the follow-up period for their urethral stricture.
Results
Successful Optilume balloon dilations without recurrence of symptoms were achieved in 24/30 (80%) patients. Failures with recurrence of strictures occurred in 20% (6/30) of cases. At a median follow-up of 353 (range: 91–818) days, 80% (24/30) of radiated patients had successful Optilume balloon dilation. Our data showed that 83% (5/6) of patients who experienced recurrence did so after 12 months. Among radiated patients without baseline incontinence, new stress incontinence developed postoperatively in 20% (3/15), while one patient had improved stress incontinence.
Conclusions
Optilume balloon dilation is a safe mechanism of treatment for urethral stricture disease in radiated patients. Early follow-up data of the treatment of urethral strictures in radiated patients suggests similar efficacy. However, long-term follow-up data is needed.
Keywords: Pelvic radiation, radiation complication, urethral dilation, urethral stricture
Highlight box.
Key findings
• Optilume drug-coated balloon dilation achieved an 80% short-term success rate in patients with radiation-induced urethral strictures.
• This procedure was associated with a low complication rate and only a 10% new onset of incontinence.
What is known and what is new?
• Drug-coated balloon dilation is effective in non-radiated urethral strictures, with previous trials showing superiority over direct vision internal urethrotomy.
• This study represents an early evaluation of Optilume balloon dilation in radiated patients, who have historically experienced high failure rates for treatment.
What is the implication, and what should change now?
• This study demonstrates the feasibility, safety, and early efficacy of Optilume in a radiation-affected population.
• Large, long-term studies are needed, but this early evidence supports expanding the use of drug-coated balloons in radiation-associated urethral disease.
Introduction
Urethral stricture disease is a common urologic pathology with a high recurrence rate, making stricture disease difficult to treat and bothersome to a patient’s quality of life. Urethral stricture disease is estimated to affect 229–627 per 100,000 men annually in the USA (1,2). Minimally invasive treatment options, such as urethral dilation and internal urethrotomy, have poor success rates and often require re-treatment when compared to urethroplasty (2). Strictures that develop following radiation are difficult to treat due to diffuse fibrotic changes and with high recurrence rates. Urethroplasty has a higher rate of success, but requires longer operative time and an extended recovery period with high rates of incontinence (3).
The Optilume® drug-coated balloon is a urethral dilation balloon with a paclitaxel coating that allows for mechanical dilation as well as direct drug delivery to a stricture site. The ROBUST III trial concludes that Optilume is safe and superior to standard direct vision internal urethrotomy (DVIU)/dilation for the treatment of recurrent anterior urethral strictures <3 cm in length (4,5). However, there have been limited studies to show efficacy in post-radiation related urethral strictures. This study aimed to clarify the safety and early efficacy of Optilume balloon dilation of urethral strictures following radiation treatment. We present this article in accordance with the STROBE reporting checklist (available at https://tau.amegroups.com/article/view/10.21037/tau-24-461/rc).
Methods
All patients undergoing Optilume balloon dilation with at least 3 months of follow-up were evaluated over the course of 27 months in a retrospective institutional setting. A total of 246 patients were identified with symptomatic urethral strictures. Thirty patients from this sample received pelvic radiation and subsequently developed symptomatic urethral strictures. Success was defined as the absence of original presenting symptoms, no need for intermittent self-dilation, and no requirement for surgical intervention within the follow-up period for their urethral stricture. Continence was assessed using subjective measures determined by the treating surgeon in discussion with the patient.
The outcomes of this study included success and continence levels post-intervention. Other outcomes included complications such as osteitis pubis, acute cystitis/pyelonephritis, and acute urinary retention. Confounding factors, such as selection bias, should be noted since not all patients were selected for the Optilume procedure, and some underwent alternative treatments.
All patients underwent intraoperative cystoscopy, either rigid or flexible. Retrograde urethrogram confirmed the location and length of the stricture (two patients had indwelling catheters, and the minimum diameter could not be assessed). Wire was passed and pre-dilation performed. In our initial cohort, we employed a 24 Fr high-pressure balloon dilation as the primary method for pre-dilation. However, we subsequently transitioned to a protocol utilizing an Amplatz dilation to 24 Fr, followed by the application of a 30 Fr × 50 mm Optilume drug-coated balloon, keeping 10 atmospheres of pressure for 10 minutes. This device was inflated for a duration of 10 minutes to ensure adequate drug delivery. Post-procedure, a 16 Fr catheter was placed with fluoroscopic guidance in most cases, unless artificial urinary sphincter or other factors dictated a different catheter. In most cases, the catheter was left in situ overnight, and the patient was instructed to remove it at home the morning after surgery.
Statistical analysis
All data were obtained by retrospective chart review and descriptive statistics as per Statistical Analyses and Methods in the Published Literature guidelines, and were analyzed using Microsoft Excel (Redmond, Washington). This study was not designed, controlled, or powered to compare groups; thus, only descriptive statistics are given.
Ethical considerations
The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by institutional ethics committee of University of South Florida (No. IRB00115897) and individual consent for this retrospective analysis was waived.
Results
A total of 246 patients with urethral stricture were treated during the study period. Among this cohort, 30 men who had a history of pelvic radiation underwent Optilume balloon dilation. The most common stricture location was the membranous urethra, affecting 70% (21/30) of these patients (Table 1). All patients (30/30) had a technically successful procedure. At a median follow-up of 353 (range: 90–818) days, 80% (24/30) of radiated patients had successful Optilume balloon dilation. Our data showed that 83% (5/6) of patients who experienced recurrence did so after 12 months. Among radiated patients, 20% (3/15) developed new incontinence after surgery, while one patient exhibited improved stress incontinence (Table 2).
Table 1. Demographics and clinical characteristics of all radiated patients undergoing Optilume balloon dilation, stratified by success and failure.
| Demographics | Total | Success | Failure |
|---|---|---|---|
| Number of patients | 30 | 24 | 6 |
| Age at surgery [mean (SD), years] | 73.1 (6.9) | 73.1 (7.1) | 73.2 (6.0) |
| Stricture length [mean (SD), cm] | 1.6 (0.8) | 1.6 (0.8) | 1.5 (0.8) |
| Stricture diameter [mean (SD), Fr] | 7.9 (4.1) | 8.3(4.0) | 6.4 (4.7) |
| Stricture location, n (%) | |||
| Penile | 1 (3.3) | 1 (4.1) | 0 (0) |
| Bulbar | 5 (16.7) | 4 (16.7) | 1 (16.7) |
| Membranous | 21 (70.0) | 16 (66.7) | 5 (83.3) |
| Bulbomembranous | 1 (3.3) | 1 (2.1) | 0 (0) |
| VUA | 2 (6.7) | 2 (8.3) | 0 (0) |
| Previous treatment, n (%) | |||
| TURP or BOP | 6 (20.0) | 5 (20.8) | 1 (16.7) |
| SPT at presentation | 7 (23.3) | 6 (25.0) | 1 (16.7) |
| CIC at presentation | 8 (26.7) | 5 (20.8) | 3 (50.0) |
| AUS or sling in place | 4 (13.3) | 4 (16.7) | 0 (0) |
| Prior urethroplasty | 2 (6.7) | 1 (4.2) | 1 (16.7) |
| Prior dilation, n (%) | |||
| 0 | 12 (40.0) | 9 (37.5) | 3 (50.0) |
| 1 | 8 (26.7) | 7 (29.1) | 1 (16.7) |
| ≥2 | 10 (33.3) | 8 (33.3) | 2 (33.3) |
AUS, artificial urinary sphincter; BOP, bladder outlet procedure; CIC, clean intermittent catheterization; SD, standard deviation; SPT, suprapubic tube; TURP, transurethral resection of the prostate; VUA, vesicourethral anastomosis.
Table 2. Clinical outcomes of radiated patients undergoing Optilume balloon dilation.
| Outcomes | Recurrent rates |
|---|---|
| Median follow-up days [range] | 353 [90–818] |
| Total recurrence, n [%] | 6/30 [20] |
| Recurrence by follow-up period, recurrence [n]/total number, n [%] | |
| <3 months | 0/3 [0] |
| ≥3 to <6 months | 0/0 [0] |
| ≥6 to <9 months | 1/11 [9.1] |
| ≥9 to <12 months | 0/1 [0] |
| ≥12 months | 5/15 [33] |
| Stress incontinence (baseline), n [%] | 15/30 [50] |
| New stress incontinence, n [%] | 3/15 [20] |
| Improved stress incontinence, n [%] | 1/15 [6.7] |
| Osteitis pubis, n [%] | 0/30 [0] |
| Acute cystitis/pyelonephritis, n [%] | 0/30 [0] |
| Acute urinary retention, n [%] | 0/30 [0] |
Discussion
Our study demonstrated that Optilume balloon dilation was both safe and effective for patients with urethral strictures following radiation. At baseline, 18/30 (60%) of our patients had at least one prior dilation, and 10/30 (33%) of our patients had two or more prior dilations (Table 1). Our study had a success rate of 80% with an average follow-up period of 375 days among patients who underwent Optilume drug-coated dilation for post-radiation urethral strictures. Our data showed that 83% (5/6) of patients who experienced recurrence did so after 12 months (Table 2). Among the patients with recurrence, one patient unfortunately died of unrelated causes before retreatment was done. Of the remaining patients with recurrence, one underwent abdominoperineal urethroplasty with delayed artificial urinary sphincter, another had a successful repeat Optilume procedure, and the last patient chose intermittent self-dilation. Two patients with adequate emptying and minimal symptoms elected no intervention.
None of the patients in our study had osteitis pubis or urinary tract infections. Fifteen of thirty patients at baseline presented with stress incontinence, and one of these patients showed improved continence after surgery. The patient who had improved incontinence is thought to have had remodeling of a “lead-pipe” membranous urethra that was promoting stress incontinence to a more malleable, coaptating sphincter.
Our findings build upon prior research on non-radiated patients with urethral strictures, including a randomized control study on the efficacy and safety of Optilume drug-coated balloon compared to standard endoscopic treatment for male anterior urethral strictures. The freedom from repeat intervention was 77.8% compared to 23.6% in the patients with the standard dilation (3). By demonstrating comparable efficacy, albeit with much shorter follow-up, our study highlights the potential of the Optilume drug-coated dilation for managing urethral strictures in this post-radiation population. Our data indicates that the recurrence rate among patients with no prior dilations (3/6) was comparable to that of patients with ≥3 prior dilations (2/6) (Table S1). In the Robust III study, participants treated with the Optilume drug-coated balloon underwent an average of 3.2 prior dilations, with 16.5% (13/79) having ≥5 prior treatments. A subgroup analysis comparing participants with ≥5 versus <5 prior dilations demonstrated a consistent treatment effect of the Optilume drug-coated balloon (6). While the small sample size in our study limits the ability to draw definitive conclusions about the influence of dilation on recurrence, combined data from the Robust III study and our findings suggest that the efficacy of the Optilume drug-coated balloon is consistent across patients regardless of the number of prior dilations.
Other intent-to-cure treatment options for urethral strictures include DVIU and urethroplasty-excision with primary anastomosis and buccal graft augmentation (7). DVIU showed less than a 50% cure rate after each individual operation in non-radiated men with urethral strictures independent of prior radiation or surgical treatment history (8,9). It was shown that the long-term management is disappointing for DVIU, showing that the stricture free rates after first, second, and third urethrotomy were 29.66%, 22.64% and 13.33%, respectively (10). The high recurrence rate associated with DVIU often results in prolonged symptomatology and necessitates repeated interventions, posing a significant challenge to patient care. In our cohort, only one patient elected to repeat Optilume, although there is not a large enough sample to have any meaningful clinical value.
In comparison, traditional balloon dilation without adjunctive drug therapy has shown similar recurrence rates to DVIU regardless of stricture characteristics, radiation history, or prior treatments (11). However, it provides a shorter operation time compared to DVIU with fewer frequent urinary tract infections (12). These balloon dilators are a safe, controlled, and minimally invasive approach to managing urethral strictures (13). Many different adjuvant therapies have been studied in addition to dilation/DVIU, but none have shown the efficacy and longevity of Optilume (14).
Urethroplasty has been a common approach for managing radiation-induced urethral strictures, demonstrating a higher success rate in terms of stricture resolution. One study found a stricture recurrence of 33% following urethroplasty, while another showed a recurrence rate of 17.7% (15,16). Despite the low recurrence rates, there are complications present with urethroplasty in managing radiation-induced urethral strictures. Percentage of 53 of patients undergoing urethroplasty developed new-onset incontinence (16). In contrast, our study showed new-onset stress incontinence among 3/15 patients who did not have baseline incontinence (20%). All three patients have functional artificial urinary sphincters at this time, with no significant urethral changes seen at the time of implantation. This shows, along with a shorter recovery period, a lower risk of new onset stress incontinence with Optilume balloon dilation. However, due to the extensive tissue changes following radiation, a clinically significant risk of incontinence remains even after this minimally invasive procedure.
This study is limited by the heterogeneity of the patients, smaller sample size, and retrospective nature, which may affect the generalizability of the findings. As Optilume has only been available in the USA since December 13, 2021 (17), our follow-up is expectedly to be short at 12 months. Of course, this cohort will need to be monitored and the outcomes updated as the data matures. Further studies with larger patient cohorts and extended follow-up durations are needed to prove long-term effectiveness.
Conclusions
Optilume balloon dilation is a safe and feasible treatment option for urethral stricture disease following pelvic radiation. Our study, with short-term follow-up, suggests that its effectiveness in radiated patients might be comparable to previous research on non-radiated patients (3,17). The observed success and low incidence of complications indicate potential benefits. Future studies with larger cohorts and longer follow-up are necessary to better assess the durability of outcomes and the role of Optilume in continence preservation for this challenging patient population.
Supplementary
The article’s supplementary files as
Acknowledgments
None.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by institutional ethics committee of University of South Florida (No. IRB00115897) and individual consent for this retrospective analysis was waived.
Footnotes
Provenance and Peer Review: This article was commissioned by the editorial office, Translational Andrology and Urology, for the series “Minimally Invasive Treatments for Urethral Stenosis”. The article has undergone external peer review.
Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://tau.amegroups.com/article/view/10.21037/tau-24-461/rc
Funding: None.
Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://tau.amegroups.com/article/view/10.21037/tau-24-461/coif). The series “Minimally Invasive Treatments for Urethral Stenosis” was commissioned by the editorial office without any funding or sponsorship. L.W. served as the unpaid Guest Editor of the series. L.W. receives consulting fees, payment for speakers bureaus, support for attending meetings, and/or travel from Laborie Medical. The authors have no other conflicts of interest to declare.
Data Sharing Statement
Available at https://tau.amegroups.com/article/view/10.21037/tau-24-461/dss
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