Increasing the dose of vardenafil on a daily basis does not improve erectile function after unilateral nerve-sparing radical prostatectomy

An update on the current status and future prospects of erectile dysfunction following radical prostatectomy

BACKGROUND

Radical prostatectomy (RP) and radiation treatment are standard options for localized prostate cancer. Even though nerve-sparing techniques have been increasingly utilized in RP, erectile dysfunction (ED) due to neuropraxia remains a frequent complication. Erectile function recovery rates after RP remain unsatisfactory, and many men still suffer despite the availability of various therapies.

OBJECTIVE

This systematic review aims to summarize the current treatments for post-RP-ED, assess the underlying pathological mechanisms, and emphasize promising therapeutic strategies based on the evidence from basic research.

METHOD

Evaluation and review of articles on the relevant topic published between 2010 and 2021, which are indexed and listed in the PubMed database.

RESULTS

Phosphodiesterase type 5 inhibitors, intracavernosal and intraurethral injections, vacuum erection devices, pelvic muscle training, and surgical procedures are utilized for penile rehabilitation. Clinical trials evaluating the efficacy of erectogenic drugs in this setting are conflicting and far from being conclusive. The use of androgen deprivation therapy in certain scenarios after RP further exacerbates the already problematic situation and emphasizes the need for effective treatment strategies.

CONCLUSION

This article is a detailed overview focusing on the pathophysiology and mechanism of the nerve injury developed during RP and a compilation of various strategies to induce cavernous nerve regeneration to improve erectile function (EF). These strategies include stem cell therapy, gene therapy, growth factors, low-intensity extracorporeal shockwave therapy, immunophilins, and various pharmacological approaches that have induced improvements in EF in experimental models of cavernous nerve injury. Many of the mentioned strategies can improve EF following RP if transformed into clinically applicable safe, and effective techniques with reproducible outcomes.

Phosphodiesterase type-5 inhibitors for erectile dysfunction following nerve-sparing radical prostatectomy: A network meta-analysis

BACKGROUND

To verify which phosphodiesterase type 5 inhibitors (PDE5is) strategy is better for erectile dysfunction (ED) following nerve-sparing radical prostatectomy (NSRP).

METHODS

This systematic literature search was conducted in MEDLINE, Web of Science and Cochrane Central Register of Controlled Trials database to identify eligible studies from the startup of these databases to 1 November, 2019. The ED recovery rate was the main outcome. Traditional pair-wise meta-analysis and multivariate random-effects network meta-analysis (NMA) were performed to explore direct and indirect comparisons, respectively. The surface under the cumulative ranking (SUCRA) probabilities was used to evaluate the efficacy of treatments.

RESULTS

A total of 14 randomized controlled trials with four kinds of PDE5is were included. Further pooled evidence suggested that PDE5is followed by NSRP had a benefit for penile rehabilitation compared to placebo using traditional pair-wise meta-analyses. Our NMA showed that Avanafil 200 mg on demand might be most likely to be the best treatment option according to the first rank of SUCRA both in NMA (SUCRA 83.5) and sensitivity analysis (SUCRA 90.2).

CONCLUSION

Avanafil 200 mg on demand has the highest probability of being the best intervention among PDE5is in treating ED following NSRP. However, more randomized controlled trials are needed to validate this in consideration of the published data regarding Avanafil is relatively small scale.

Generating comprehensive comparative evidence on various interventions for penile rehabilitation in patients with erectile dysfunction after radical prostatectomy: a systematic review and network meta-analysis

Background

We aim to present a comprehensive comparison of various treatments in the management of penile recovery after radical prostatectomy (RP) and provide recommendations for future research.

Methods

Literature search of electronic databases including PubMed, the Cochrane Library, Embase, PsycInfo, and Web of Science, and manual retrieval were conducted from inception through March 2020. “Erectile dysfunction” and “prostatectomy” were used as the Mesh terms. The patients, intervention, comparison, outcome, and study design (PICOS) approach were used to define study eligibility. Two authors independently selected studies, evaluated the methodological quality, and extracted data using Cochrane Collaboration’s tools. The data analysis was completed by STATA version 14.2.

Results

A total of 24 studies with 3,500 patients were incorporated in the final analysis after screening 6,131 records. Our findings indicated that vacuum constriction devices (VCD) ranked 1st which meant that patients in VCD group had the best effect regarding mean IIEF scores within 3 months after RP, and no significant difference was observed between VCD and VCD with 20 mg/day tadalafil (V20DT) (MD: 5.44; 95% CI: −0.81 to 11.69). VCD and 50 mg/day sildenafil (VC50DS) showed superiority over 50 mg/day sildenafil (50DS) (MD: 3.75; 95% CI: 2.74–4.76) and intraurethral alprostadil 125–250 µg (MD: 3.05; 95% CI: 0.38 to 5.72), respectively. Moreover, V20DT showed significant superiority over the other interventions for ≥6 months mean International Index Erectile of Function (IIEF) scores after RP. Monotherapy appeared to have similar efficacy in terms of mean IIEF scores and proportion of patients return to baseline, and the effect of phosphodiesterase type 5 inhibitors (PDE5is) did not seem to be affected by the patterns of administration (regular or on demand).

Conclusions

The combination therapy showed certain advantages over monotherapy, and we recommended the combination of VCD and PDE5is to be considered in the clinical management of penile rehabilitation after RP.

Current management strategy of treating patients with erectile dysfunction after radical prostatectomy: a systematic review and meta-analysis

The aim of this study is to present a summary of current evidence concerning the various treatments in the management of penile rehabilitation after radical prostatectomy (RP) and provide recommendations for future research. Randomized controlled trials (RCTs) were identified from electronic databases including PubMed, the Cochrane Library, Embase, and Web of Science from inception through March 2020 with no limitation to language. Comparable data from each study were combined in a meta-analysis where possible, otherwise data were synthesized narratively. The data analysis was completed by Review Manager version 5.3. A total of 39 RCTs were included in this study. At present, phosphodiesterase type 5 inhibitors (PDE5is) remain the first-line treatment for patients with erectile dysfunction (ED) after RP. Compared with the placebo group, patients in regular PDE5is group (mean difference (MD): 0.76; 95% confidence interval (CI): 1.69-4.44; p < 0.0001) and on demand group (MD: 3.92; 95% CI: 2.95-4.88; p < 0.00001) had a significantly higher mean Erectile Function domain of the International Index of Erectile Function (IIEF-EF) scores within 3 months after RP. As for the proportion of IIEF-EF ≥ 22, patients in regular PDE5is group and on demand PDE5is group had significantly higher proportion than those in placebo group 6 months after RP, and the odds ratios were 1.87 (95% CI: 1.32-2.66; p = 0.0005) and 2.17 (95% CI: 1.20-3.93; p = 0.01), respectively. No significant difference was observed between regular PDE5is group and on demand group regardless of mean IIEF-EF score or the proportion of IIEF-EF ≥ 22. Intracorporeal injection therapy seemed to have similar efficacy to PDE5is. The International Index of Erectile Function-5 items (IIEF-5) scores were significantly higher in vacuum constriction devices group than control group at 6-9 months after RP (MD: 6.70, 95% CI: 2.30-11.10, p = 0.003) with great between-study heterogeneity (p = 0.06, I² = 72%). The other therapeutics including low-intensity extracorporeal shockwave therapy, statin therapy, psychotherapy interventions, and pelvic floor muscle training plus electrical stimulation showed certain improvement on erectile function. We found that the combination therapy showed certain advantages over monotherapy. Currently, PDE5is-based combination therapy remains the mainstream treatment for ED after RP. Intracorporeal injection therapy and vacuum therapy could be served as alternative treatments if PDE5is are ineffective and contraindicated.

Functional recovery after radical prostatectomy for prostate cancer

With the enthusiasm regarding robotic application in radical prostatectomy in accordance with the widespread use of serum prostate-specific antigen as a screening test, the number of surgeries performed for complete removal of the gland is increasing continuously. However, owing to the adjacent anatomical location of the prostate to the nerve and urethral sphincter complex, functional recovery, namely improvement from post-prostatectomy incontinence (PPI) and post-prostatectomy erectile dysfunction, still remains a main problem for patients who are reluctant to undergo surgery and tend to choose alternative ways instead. Since the late 1980s, the introduction of radical prostatectomy by open surgical modalities, the depth of the anatomical understanding of the structure surrounding the prostate is getting tremendous, which leads to the development of new surgical modalities and techniques that are consequently aimed at reducing the incidences of PPI and erectile dysfunction. Briefly, recent data from robotic radical prostatectomy, particularly on PPI, are quite acceptable, but by contrast, the reported potency regain rate still remains <20%, which indicates the need for advanced surgical modification to overcome it. In this review, the authors summarized the recent findings on the anatomy and surgical techniques reported up to now.

Penile rehabilitation for postprostatectomy erectile dysfunction

BACKGROUND

Despite efforts to preserve the neurovascular bundles with nerve-sparing surgery, erectile dysfunction remains common following radical prostatectomy. Postoperative penile rehabilitation seeks to restore erectile function but results have been conflicting.

OBJECTIVES

To evaluate the effects of penile rehabilitation strategies in restoring erectile function following radical prostatectomy for prostate cancer.

SEARCH METHODS

We performed a comprehensive search of multiple databases (CENTRAL, MEDLINE, Embase), the Cochrane Library, Web of Science, clinical trial registries (ClinicalTrials.gov, International Clinical Trials Registry Platform) and a grey literature repository (Grey Literature Report) from their inception through to 3 January 2018. We also searched the reference lists of other relevant publications and abstract proceedings. We applied no language restrictions.

SELECTION CRITERIA

We included randomised or quasi-randomised trials with a parallel or cross-over design.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. Two review authors independently screened the literature, extracted data, assessed risk of bias and rated quality of evidence according to GRADE on a per-outcome basis. Primary outcomes were self-reported potency, erectile function measured by validated questionnaires (with potency defined as an International Index of Erectile Function (IIEF-EF) score of 19 or greater and or an IIEF-5 of score of 17 or greater) and serious adverse events. For all quality of life assessments on a continuous scale, higher values indicated better quality of life.

MAIN RESULTS

We included eight randomised controlled trials with 1699 participants across three comparisons. This abstract focuses on the primary outcomes of this review only.Scheduled phosphodiesterase type 5 inhibitors (PDE5I) versus placebo or no treatmentScheduled PDE5I may have little or no effect on short-term (up to 12 months) self-reported potency (risk ratio (RR) 1.13, 95% confidence interval (CI) 0.91 to1.41; very low quality evidence), which corresponds to 47 more men with self-reported potency per 1000 (95% CI 33 fewer to 149 more) and short-term erectile function as assessed by a validated instrument (RR 1.11, 95% CI 0.80 to 1.55; very low quality evidence), which corresponds to 28 more men per 1000 (95% CI 50 fewer to 138 more), but we are very uncertain of both of these findings. Scheduled PDE5I may result in fewer serious adverse events compared to placebo (RR 0.32, 95% CI 0.11 to 0.94; low quality evidence), though this does not appear biologically plausible and may represent a chance finding. We are also very uncertain of this finding. We found no long-term (longer than 12 months) data for any of the three primary outcomes.Scheduled PDE5I versus on-demand PDE5I Daily PDE5I appears to result in little to no difference in both short-term and long-term (greater than 12 months) self-reported potency (short term: RR 0.97, 95% CI 0.62 to 1.53; long term: RR 1.00, 95% CI 0.60 to 1.67; both very low quality evidence); this corresponds to nine fewer men with self-reported short-term potency per 1000 (95% CI 119 fewer to 166 more) and zero fewer men with self-reported long-term potency per 1000 (95% CI 153 fewer to 257 more). We are very uncertain of these findings. Daily PDE5I appears to result in little to no difference in short-term and long-term erectile function (short term: RR 1.00, 95% CI 0.65 to 1.55; long term; RR 0.74, 95% CI 0.48 to 1.14; both very-low quality evidence), which corresponds to zero men with short-term erectile dysfunction per 1000 (95% CI 80 fewer to 125 more) and 119 fewer men with long-term erectile dysfunction per 1000 (95% CI 239 fewer to 64 more). We are very uncertain of these findings. Scheduled PDE5I may result in little or no effects on short-term adverse events (RR 0.69 95% CI 0.12 to 4.04; very low quality evidence), which corresponds to seven fewer men with short-term serious adverse events (95% CI 18 fewer to 64 more), but we are very uncertain of these findings. We found no long-term data for serious adverse events.Scheduled PDE5I versus scheduled intraurethral prostaglandin E1At short-term follow-up, daily PDE5I may result in little or no effect on self-reported potency (RR 1.10, 95% CI 0.79, to 1.52; very low quality evidence), which corresponds to 46 more men per 1000 (95% CI 97 fewer to 241 more). Daily PDE5I may result in a small improvement of erectile function (RR 1.64, 95% CI 0.84 to 3.20; very low quality evidence), which corresponds to 92 more men per 1000 (95% CI 23 fewer to 318 more) but we are very uncertain of both these findings. We found no long-term (longer than 12 months) data for any of the three primary outcomes.We found no evidence for any other comparisons and were unable to perform any of the preplanned subgroup analyses based on nerve-sparing approach, age or baseline erectile function.

AUTHORS' CONCLUSIONS

Based on mostly very-low and some low-quality evidence, penile rehabilitation strategies consisting of scheduled PDE5I use following radical prostatectomy may not promote self-reported potency and erectile function any more than on demand use.

Efficacy and safety of short- and long-term, regular and on-demand regimens of phosphodiesterase type 5 inhibitors in treating erectile dysfunction after nerve-sparing radical prostatectomy: a systematic review and meta-analysis

Background

We performed a meta-analysis to evaluate the efficacy and safety of short-term (≤6 months) and long-term (>6 months), regular (OaD) and on-demand (PRN) regimens of phosphodiesterase type 5 inhibitors (PDE5-Is) in treating erectile dysfunction (ED) after nerve-sparing radical prostatectomy (NSRP).

Methods

We conducted a literature search in August 2016. Sources included PubMed, EMBASE, and MEDLINE databases. The main outcome was International Index of Erectile Function-Erectile Function (IIEF-EF) domain score, and the secondary outcome was treatment-emergent adverse events (TEAEs).

Results

Eight articles involving 13 randomized controlled trials (RCTs) were used in this analysis: they suggested that PDE5-Is can improve the IIEF-EF distinctly in comparison with placebo in short and long term (mean difference [MD]: 2.26, 95% confidence interval [CI]: 1.45–3.08, P<0.00001, and MD: 4.5, 95% CI: 3.6–5.4, P<0.00001), and long-term use of PDE5-Is (>6 months) can improve the IIEF-EF distinctly in comparison with short-term use of PDE5-Is (≤6 months) (MD: 3.9, 95% CI: 3.01–4.8, P<0.00001). OaD of PDE5-Is significantly improved the IIEF-EF compared to placebo in short and long term (MD: 4.08, 95% CI: 3.2–4.97, P<0.00001, and MD: 4.74, 95% CI: 3.79–5.69, P<0.00001). No significant differences were found in IIEF-EF changes between PRN and placebo (≤6 months) (MD: 2.64, 95% CI: −0.87 to 6.14, P=0.14), and between PRN and OaD group (>6 months) (MD: −0.58, 95% CI: −9.86 to 8.74, P=0.91). There were more TEAEs in PDE5-Is group in comparison with placebo (odds ratio [OR]: 1.55, 95% CI: 1.26–1.91, P<0.0001), and TEAEs in OaD group were not significantly different from those seen in PRN group (OR: 1.05, 95% CI: 0.78–1.4, P=0.77).

Conclusion

Our meta-analysis suggests that PDE5-Is are efficient and safe for treatment of ED after NSRP, and we should choose the regular regimen for short term and regular or on-demand regimen for long term. Further high-quality RCTs are needed to validate this result.

Comparisons of regular and on-demand regimen of PED5-Is in the treatment of ED after nerve-sparing radical prostatectomy for Prostate Cancer

Phosphodiesterase type-5 inhibitors (PDE5-Is) have been recommended as first line therapy for erectile dysfunction for patients received nerve-sparing radical prostatectomy for prostate cancer. We examed the efficiency of PDE5-Is and considered the optimal application. Systematic search of PubMed, Embase and the Cochrane Library was performed to identify all the studies. We identified 103 studies including 3175 patients, of which 14 were recruited for systematic review. Compared with placebo, PDE5-Is significantly ameliorated the International Index of Erectile Function-Erectile Function domain score (IIEF) scores (MD 4.89, 95% CI 4.25-5.53, p < 0.001). By network meta-analysis, sildenafil seems to be the most efficiency with a slightly higher rate of treatment-emergent adverse events (TEATs), whereas tadalafil had the lowest TEATs. In terms of IIEF scores, regular regimen was remarkably better than on-demand (MD 3.28, 95% CI 1.67-4.89, p < 0.001). Regular use was not associated with higher proportion of patients suffering TEATs compared with on-demand (RR 1.02, 95% CI 0.90-1.16, p = 0.72). Compared with placebo, PDE5-Is manifested significantly improved treatment outcomes. Overall, regular regimen demonstrated statistically pronounced better potency than on-demand. Coupled with the comparable rate of side effects, these findings support the regular delivery procedure to be a cost-effective option for patients.

Have rates of erectile dysfunction improved within the past 17 years after radical prostatectomy? A systematic analysis of the control arms of prospective randomized trials on penile rehabilitation

Based on case series, potency rates after radical prostatectomy (RPE) differ substantially and - furthermore - it remains unclear whether they have improved in more recent surgical series. The purpose of this study was to investigate whether potency rates after RPE have improved over the years. A systematic analysis of the control arms of all randomized controlled trials (RCT; n = 11) on penile rehabilitation after RPE was carried out. In total, 2009 patients were included in these RCTs, 685 thereof in the respective control arms, who were either observed or received placebo. Assessment of erectile function in these studies was carried out by the Sexual Encounter Profile (SEP) or the International Index of Erectile Function (IIEF). Eight trials used SEP3 as study endpoint. The rate of positive response to SEP3 (=erectile function sufficient for successful intercourse) in the control arms was 20% in 1997 (year of publication), 10% in 2003, 19% in 2004, 25% in 2008, 21% in 2010, 67% in 2011, 10% in 2013, and 22% in 2014. Eight RCTs assessed the IIEF-EF, yet results were not reported uniformly. In the control arms the IIEF-EF was 9.2 (year of publication 2003), 13.3 (2004), 8.8 (2008), 25% ≥22.0 (2008), 17.4 (2010), 58% ≥26.0 (2011), 9.3 (2013), and 11.6 (2014). Limitations of this analysis are a positive selection bias regarding patient recruitment, surgical approach, and the non-uniform inclusion and outcome criteria. This systematic analysis of the control arms of all RCTs on penile rehabilitation after nerve-sparing RPE shows (i) that the rate of undisturbed erectile function is in the range 20-25% in most studies and (ii) that these rates have not substantially improved or changed over the past 17 years.

Impact of penile rehabilitation with low-dose vardenafil on recovery of erectile function in Japanese men following nerve-sparing radical prostatectomy

Erectile dysfunction (ED) is a major complication after radical prostatectomy (RP); however, debate continues regarding the efficacy of penile rehabilitation in the recovery of the postoperative erectile function (EF). This study included a total of 103 consecutive sexually active Japanese men with localized prostate cancer undergoing nerve-sparing RP, and analyzed the postoperative EF, focusing on the significance of penile rehabilitation. In this series, 24 and 79 patients underwent bilateral and unilateral nerve-sparing RPs, respectively, and 10 or 20 mg of vardenafil was administered to 35 patients at least once weekly, who agreed to undergo penile rehabilitation. Twelve months after RP, 48 (46.6%) of the 103 patients were judged to have recovered EF sufficient for sexual intercourse without any assistance. The proportion of patients who recovered EF in those undergoing penile rehabilitation (60.0%) was significantly greater than that in those without penile rehabilitation (38.2%). Of several parameters examined, the preoperative International Index of Erectile Function-5 (IIEF-5) score and nerve-sparing procedure were significantly associated with the postoperative EF recovery rates in patients with and without management by penile rehabilitation, respectively. Furthermore, univariate analysis identified the preoperative IIEF-5 score, nerve-sparing procedure and penile rehabilitation as significant predictors of EF recovery, among which the preoperative IIEF-5 score and nerve-sparing procedure appeared to be independently associated with EF recovery. Considering these findings, despite the lack of independent significance, penile rehabilitation with low-dose vardenafil could exert a beneficial effect on EF recovery in Japanese men following nerve-sparing RP.

Daily dosing of PDE5 inhibitors: where does it fit in?

To provide a critical contemporary review of daily PDE5-inhibitor (PDE5-I) use in urological and nonurological conditions. PDE5-Is can be taken up to once a day. However, at present only tadalafil is approved for use in both erectile dysfunction (ED) and benign prostate hyperplasia (BPH) with lower urinary tract symptoms (LUTS). Evolving research in penile rehabilitation, Peyronie's disease, male infertility, pulmonary arterial hypertension, muscular dystrophy and Raynaud's phenomenon shows these therapeutic areas may also benefit from PDE5i therapy. This review examines the role of chronic PDE5 inhibition in ED, BPH-LUTS and other therapeutic targets which may shape our clinical practice in the years to come.

Current penile-rehabilitation strategies: Clinical evidence

We review the current strategies used for penile rehabilitation (PR) after a radical prostatectomy, where PR is defined as the attempt to restore spontaneous erectile function so that the patient can generate erections with no need for erectile aids. We searched PubMed for relevant reports, using the keywords ‘radical prostatectomy’, ‘penile rehabilitation’, ‘phosphodiesterase inhibitors’, ‘vacuum erection device’, ‘injection therapy’, ‘urethral suppository’, and ‘erectile dysfunction’. In all, 155 articles were identified and reviewed, and had a level of evidence ranging from 1b-4. The use of PR strategies should be based on the patient’s goals after a thorough explanation of realistic expectations, and the risks and consequences of the various treatment options. While a multitude of studies suggest a benefit with PR strategies, there are no established, proven regimens. Further research is needed to establish the optimal approaches to PR.