Cancer is considered as the leading cause of death and the single most important factor in threatening life expectancy in the twenty-first century. The estimated incidence of prostate cancer 1,276,106 (7.1%) in 2018 in the world [1]. Also, prostate cancer is the second most commonly diagnosed cancer and the leading cause of cancer death in males. Robot-assisted laparoscopic radical prostatectomy (RARP) may result in better early continence outcomes when compared to other approaches, including open and laparoscopic radical prostatectomy. The incontinence rates at 3, 12, 24-36 months after RARP were approximately 78, 84 and 88% with continence defined as 0 pads use daily, respectively. Pelvic floor muscle training (PFMT) for urinary incontinence (UI) occurred after prostatectomy was recommended as Grade B. The previous studies conducting PFMT for patients with radical prostatectomy assessed 24-hour pad weight or UI-specific quality of life (QOL) questionnaires as main outcome. However, there are no randomized controlled studies (RCT) that assessed pelvic floor muscle (PFM) function quantitatively. The purpose of this study was to investigate the effect of supervised PFMT on PFM function for male patients with UI after RARP.

The current study was designed as assessor-blinded two-armed RCT. The supervised PFMT group was compared with control group. The participants who were scheduled RARP in our hospital were recruited in the current study from February 2017 to May 2019. Inclusion criteria was more than 1 month before RARP to perform preoperative PFMT. Exclusion criteria were serious psychiatric, neurological diseases or lower urinary tract infection. The study was approved by the Ethics Committee in our institution. All participants were given written informed consent before entering the current study. Power calculation was based on the former study conducted 24-hour pad weight at 3 months after radical prostatectomy as primary endpoint [2]. The sample size was set at 27 participants per group to provide a power of 80% and a significance level of 5% for detecting the difference between groups. A final sample size was set at 30, which considered 3 participants as dropouts in each group. We randomly assigned men to receive either supervised PFMT or control group. The participants were evaluated by the following outcomes. The primary endpoint was conducted 24-hour pad weight (g) at 3 months after RARP. Other outcomes were PFM function including resting anorectal pressure, maximum anorectical squeeze pressure, duration, and Expanded Prostate Cancer Index Composite as QOL questionnaire. With regard to PFM function, a manometer with anal sensor (PeritronTM cat 9300A; Laborie, Canada) was used for quantitative PFM assessment. All participants were lying on the bed in a lateral position with knees drawn up at 45º and a pillow placed under the head. An assessor gave standardized instructions to “squeeze and lift or tighten and pull up the PFM as hard as you can” for maximum contraction of the PFM. We defined the PFM function as the percentage changes in resting anorectal pressure, maximum anorectal squeeze pressure equal that the value at each time point divided by the preoperative value, multiplied by 100. These outcomes were assessed before RARP, 7days, 1, 3, 6, 12 months after RARP. In supervised PFMT group, the participants were delivered one-to-one PFMT guidance, which performed three times preoperatively, and at 7 days, 1, 3, 6, 12 months after RARP. They received verbal information about pelvic floor anatomy and function using an anatomical male pelvic model. They were taught isolated contraction of PFM without contracting the other muscles, including the outer abdominal muscles, muscles of the hip joint with verbal instruction and palpation of PFM. Home-based PFMT was performed throughout the current study. In control group, the participants were instructed and given booklets about PFMT and lifestyle advice verbally, as daily care in our hospital. Statistical analysis was performed using SPSS version 23.0. Data distribution was assessed with the Shapiro-Wilk test for continuous variables. For between group comparisons, we used the two-sample t test with normally distributed data, and the Mann–Whitney U test with not normally distributed data. The significance level was set at p<0.05.

A total of 50 participants scheduled RARP were completed in the current study (supervised PFMT group: 24 men, control group: 26 men). The characteristics of included participants, such as age, body mass index, serum prostate specific antigen, console time, nerve preservation, estimated blood loss, prostate size, pathologic T stage, smoking history, grison score were not significant differences between supervised PFMT and control group. Forty-eight of the 50 participants (96.0%) who underwent RARP had UI at 7 days after surgery. 24-hour pad weight in supervised PFMT group was significantly lower than that in the group control group at 3 and 12 months after surgery (p<0.05). The percentage changes of maximum anorectal squeeze pressure in supervised PFMT and control group were median: 94.7 (16.6-441.3) and median: 67.2 (21.9-196.5) at 7 days, median:126.0 (47.0-352.6) and median: 94.6 (37.7-267.7) at 3 months, respectively. The percent changes in maximum anorectal squeeze pressure in supervised PFMT group was significantly higher compared to control group (p<0.05). Other parameters of PFM function did not change significantly between groups. There was no significant difference in QOL questionnaire score between two groups.

To our knowledge, this is the first study to investigate the effect of supervised PFMT on PFM function for male patients with UI after RARP. We found that higher maximum anorectal squeeze pressure in supervised PFMT group compared to control group. A manometer with an anorectal sensor was used to assess the levator ani muscle as PFM function in men since anorectal measurement is only a practical option. In our preliminary study, the reliability assessment of the resting anorectal pressure and the maximum anorectal squeeze pressure were evaluated, and found the intra- and inter-rater reliability of resting pressure, anorectal squeeze pressure were substantial to almost perfect for two examiners (unpublished data). The previous single-arm study performed PFMT for the patients after radical prostatectomy demonstrated that PFM strength improved continuously until 6 months after surgery [3]. The limitation of the previous study was that natural recovery could not be excluded. The current study showed supervised PFMT maintained PFM function (anorectal squeeze pressure) after RARP by conducting RCT.
     There was a significant improvement of UI in supervised PFMT group than control, which suggests that PFMT prevented the deterioration of postoperative UI. This is because supervised PFMT, which provided guidance on PFM contraction by visual inspection and palpation, improved the PFM function, rather than using booklets and verbal explanations of PFMT.

The results of the current study showed that PFM function played an essential role in maintaining continence after RARP. Pre- and post-operative supervised PFMT was beneficial for patients with UI after RARP to progress PFM function, leading to the improvement incontinence.

Bray F, et al. GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries. CA Cancer J Clin. 2018;68(6):394-424
Mariotti G et al. Early recovery of urinary continence after radical prostatectomy using early pelvic floor electrical stimulation and biofeedback associated treatment. J Urol. 2009;181(4):1788-93.
Zachovajeviene B et al. Dynamics of pelvic floor muscle functional parameters and their correlations with urinary incontinence in men after radical prostatectomy. Neurourol Urodyn. 2017;36(1):126-131.