Outcomes of a Noninferiority Randomised Controlled Trial of Surgery for Men with Urodynamic Stress Incontinence After Prostate Surgery (MASTER) - Beyond the Abstract

Persistent stress urinary incontinence (SUI) following surgery for prostate cancer is the strongest negative predictor of health-related quality-of-life after radical prostatectomy.1 Post-prostatectomy incontinence (PPI) is highly prevalent based on validated patient-reported outcome measures and 5% of all patients ultimately require surgical treatment.2,3 The artificial urinary sphincter (AUS) is widely regarded as the surgical treatment of choice for bothersome PPI, but the development of several types of male sling over the past decade has led to their increasing use. It is generally believed that the AUS is more suitable for patients with moderate-to-severe SUI whereas the male slings are better suited to those with mild-to-moderate SUI.4 However, these surgical options have not previously been directly compared to assess efficacy and safety.


The MASTER trial is a randomised, multicentre trial comparing the AUS and passive suburethral synthetic sling (male sling) in men with bothersome post-prostatectomy SUI that had persisted for at least 12 months following prostate surgery despite conservative treatment and pelvic floor muscle training.5 SUI had to be confirmed on urodynamic investigation and men had to be willing to be randomised between the two surgical options. The trial was conducted in 27 centres in the United Kingdom over a 4 year period and a total of 380 men were randomised (190 in each group). Pure SUI was seen in 16% and the vast majority had mixed incontinence. Given the known difficulties with maintaining surgical equipoise in surgical trials, it is notable that only 194 of 715 eligible patients were excluded for this reason (i.e., surgeon or patient had a preference for one option over another). The trial was designed to prove non-inferiority of the male sling compared to the AUS, with a non-inferiority margin set at 15% based on the outcomes of qualitative interviews on what men considered acceptable. The findings from these qualitative interviews will be published in the future and will provide fascinating insights into the values and preferences of men undergoing surgery for PPI. The primary outcome measure was any self-reported urinary incontinence at 12 months after randomisation. The strict definition of urinary incontinence was based on any degree of reported leakage when men were asked the following 2 questions from the validated ICIQ-UI questionnaire: ‘how often do you leak urine’ and ‘how much urine do you leak’. A less strict definition of success also included those who responded that they leaked ‘once a week or less’ or leaked a ‘small amount’. Pad usage and 24-hour pad weights were included amongst the secondary outcome measures.

The two arms were well-matched at baseline with a mean age of 68 and 69 years, average pad usage of 3 pads per day, and 24-hour pad weights of 256g and 267g for the male sling and AUS, respectively. The principal finding was that complete continence (dry) rates were surprisingly low at 13% for the male sling group and 16% for the AUS group at 1 year after randomisation. However, this was based on the strict definition described above. Using the less strict definition of leaking ‘once a week or less’, or leaking a ‘small amount’, the success rates were 34% for the male sling and 35% for the AUS. This is still lower than the expected success rates based on previous multicentre studies.6 However, although the frequency of leakage was similar between the groups, the amount of leakage was significantly lower for the AUS (moderate or severe incontinence 28% for male sling vs. 18% for AUS). Despite the low rates of continence, satisfaction based on the ICIQ-satisfaction was still reported to be high at 72% and 91% for the male sling and AUS, respectively. Furthermore, 72% and 85% of men who underwent male sling and AUS, respectively, would recommend the procedure to a friend. Although the male sling was shown to be non-inferior in the primary outcome measures, the AUS was still more effective, from the satisfaction point of view, for all degrees of incontinence (<250g or >250g). These data highlight the importance of understanding patients’ expectations from treatment and their values. Although unlikely to be dry, men seem to be sufficiently improved and satisfied with either option. Dry rates were better in those that had pure SUI. The rate of serious adverse events was low, but the male sling group had significantly higher rates of infections, new bladder symptoms, and surgical site pain. Overall, there were 16 readmissions; 13 men in the male sling group required reoperation within 1 year (12 underwent AUS insertion), compared to only 3 in the AUS group (balloon repositioning or replacement). Interestingly, patients who had prior radiotherapy treatment had a significantly higher risk of reoperation whichever arm they were in (53% reoperation in those with prior radiotherapy compared to 18% in those without). The follow-up period is currently too short to assess AUS device-related complications, but the planned 5-year analysis will answer questions about the long-term safety and efficacy of both options.

In summary, the MASTER trial has provided level 1 evidence that the male sling and AUS are both effective for post-prostatectomy SUI in men in the short-term. Dry rates are low with both options, but overall satisfaction is still high, with all secondary outcomes favouring the AUS. These results will aid patient counseling and will help to set realistic expectations prior to surgery.

Written by: Sachin Malde,1 & Arun Sahai, PhD, FRCS (Urol)2

  1. Consultant Urological Surgeon, Guy's and St Thomas' NHS Foundation Trust
  2. Consultant Urological Surgeon & Reader in Urology, Guy’s Hospital & King’s College London, London


References:

  1. Penson DF, Feng Z, Kuniyuki A, McClerran D, Albertsen PC, Deapen D, et al. General quality of life 2 years following treatment for prostate cancer: what influences outcomes? Results from the prostate cancer outcomes study. J Clin Oncol. 2003;21(6):1147-54.
  2. Donovan JL, Hamdy FC, Lane JA, Mason M, Metcalfe C, Walsh E, et al. Patient-Reported Outcomes after Monitoring, Surgery, or Radiotherapy for Prostate Cancer. N Engl J Med. 2016;375(15):1425-37.
  3. Nam RK, Herschorn S, Loblaw DA, Liu Y, Klotz LH, Carr LK, et al. Population based study of long-term rates of surgery for urinary incontinence after radical prostatectomy for prostate cancer. J Urol. 2012;188(2):502-6.
  4. Averbeck MA, Woodhouse C, Comiter C, Bruschini H, Hanus T, Herschorn S, et al. Surgical treatment of post-prostatectomy stress urinary incontinence in adult men: Report from the 6th International Consultation on Incontinence. Neurourol Urodyn. 2019;38(1):398-406.
  5. Abrams P, Constable LD, Cooper D, MacLennan G, Drake MJ, Harding C, et al. Outcomes of a Noninferiority Randomised Controlled Trial of Surgery for Men with Urodynamic Stress Incontinence After Prostate Surgery (MASTER). Eur Urol. 2021;79(6):812-23.
  6. Tutolo M, Cornu JN, Bauer RM, Ahyai S, Bozzini G, Heesakkers J, et al. Efficacy and safety of artificial urinary sphincter (AUS): Results of a large multi-institutional cohort of patients with mid-term follow-up. Neurourol Urodyn. 2019;38(2):710-8.

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