Comparison of Validated Instruments Measuring Sexual Function in Men

Evaluation of bi-directional causal association between periodontal disease and erectile dysfunction: a two-sample Mendelian randomization study

BACKGROUND

The association between periodontal disease (PD) and erectile dysfunction (ED) has been well-documented in observational studies. However, observational studies are vulnerable to reverse causality and confounding factors, making the inference of causal-effect relationships challenging. Contrary to the current belief, Mendelian randomization (MR) can be applied to comprehensively assess the bi-directional causal effects between PD and ED.

METHODS

A two-sample MR analysis was performed using pooled statistics from genome-wide association studies involving European populations with PD (12,289 patients with PD and 22,326 controls) and ED (6,175 patients with clinically diagnosed ED and 217,630 controls). In this MR analysis, three methods--the inverse-variance weighted (IVW) average, weighted median, and MR-Egger regression methods--were used to evaluate the causal relationships between PD and ED.

RESULTS

According to the IVW analysis results, genetically predicted PD did not have a causal effect on ED (odds ratio 1.07, 95% confidence interval 0.96-1.20, p = 0.22). Furthermore, there was no clear indication of a significant causal effect of ED on PD in the reverse MR analysis (odds ratio 0.98, 95% confidence interval 0.90-1.08, p = 0.74). The results of the MR-Egger regression and weighted median methods were consistent with those of the IVW method. Based on the sensitivity analysis results, a major bias from genetic pleiotropy was unlikely to distort the causal estimates.

CONCLUSION

The present study does not support a causal effect between PD and ED.

CLINICAL RELEVANCE

From the perspective of genetics, PD does not appear to be a risk factor for the development of ED.

Einfluss von Bewegungstherapie auf sexuelle Dysfunktionen bei Patienten mit Prostatakarzinom als Begleitung (oder nach) medizinischer Tumorbehandlung – Ein systematisches Review

Hintergrund Sexuelle Dysfunktionen sind Lebensqualität mindernde Nebenwirkungen von Standardtherapien bei Prostatakarzinom.

Ziel Diese Untersuchung erfasst den aktuellen wissenschaftlichen Kenntnisstand bezüglich Effektivität von Bewegungstherapie zur Kompensation sexueller Dysfunktionen in Folge von Standardtherapien bei Prostatakarzinom.

Methode Systematisches Review in Anlehnung an „Preferred Reporting Items for Systematic Reviews and Meta-Analyses“ (PRISMA). Die Literaturrecherche wurde von 2 unabhängigen Gutachter*innen in den Datenbanken Pubmed und PEDro durchgeführt. Eingeschlossen wurden Randomized Controlled Trials (RCT) mit dem American Society of Clinical Oncology (ASCO) Evidenzlevel I, die sexuelle Funktionen von Patienten mit standardtherapierten Prostatakarzinom unter Bewegungstherapie evaluieren.

Ergebnisse 17 Publikationen mit 1175 Patienten mit Prostatakarzinom erfüllten die Einschlusskriterien. 11 Studien berichten signifikante Verbesserungen der sexuellen Funktionen durch Bewegungstherapie.

Schlussfolgerung Da die Mehrzahl der Studien nicht vergleichbar war, ist keine generalisierte Aussage bezüglich der Wirksamkeit von Bewegungstherapie möglich. Weitere kontrollierte Studien sind unabdingbar, um den Einfluss von Bewegungstherapie auf sexuelle Dysfunktion bei Patienten mit Prostatakarzinom unter Standardtherapien aufzuzeigen.

The Association Between Periodontitis and Erectile Dysfunction: A Systematic Review and Meta-Analysis

The objective of this study is to investigate the association between periodontitis (PD) and erectile dysfunction (ED).A systematic review and meta-analysis on data was extracted and conducted according to PRISMA. Relevant articles were selected from a literature search using MEDLINE, EMBASE, Scopus, Web of Science and CENTRAL from inception until August 2, 2020. Both randomized and nonrandomized controlled studies were included. Case reports, case series, nonsystematic reviews and trials published as abstract were excluded. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were used to estimate the association between PD and the risk of ED. The meta-analysis was conducted with RevMan 5.3. Methodological quality assessment was carried out using the Newcastle-Ottawa Quality Assessment Scale and the quality of evidence was assessed using the GRADE approach.Six articles (215008 subjects) were included for analysis. Of the participants, 38,675 cases were compared to 1,76,333 healthy controls. Based on the random effects model, periodontitis was associated with an increased risk of ED (OR = 2.56, 95% CI: 1.70-3.85) as compared with the non-periodontitis individuals. The findings were statistically significant with a p < .0001. The statistical heterogeneity was high across all studies (I2 = 98%, p < .00001). Estimates of total effects were generally consistent with the sensitivity and subgroup analyses.Within the limits of the available evidence, our review and meta-analysis showed that a significant association exists between the PD and ED. The results should be interpreted with caution due to high degree of inconsistency across all the studies.

Interpreting Patient Reported Urinary and Sexual Function Outcomes across Multiple Validated Instruments

PURPOSE

Comparing patient reported outcomes such as urinary and erectile function across institutions is critical for prostate cancer research and quality assurance. Such comparisons are complicated due to the use of different questionnaires. We aimed to develop a method to convert scores among 4 commonly used instruments.

MATERIALS AND METHODS

Patient reported data on urinary and sexual function were collected on 1,284 men with localized prostate cancer using the EPIC-26 (Expanded Prostate Index Composite), PCI (UCLA Prostate Cancer Index), SHIM (Sexual Health Inventory for Men) and I-PSS (International Prostate Symptom Scale) questionnaires. We investigated several methods to convert scores among questionnaires.

RESULTS

Conversion between EPIC and PCI urinary and sexual function subscales was best achieved using only the subset of questions asked on both questionnaires. For the conversion between EPIC or PCI erectile function scores and SHIM scores, we defined thresholds of poor, intermediate and good function as EPIC/PCI 0 to 40 and SHIM 1 to 7, EPIC/PCI 41 to 59 and SHIM 8 to 16, and EPIC/PCI 60 to 100 and SHIM 17 to 25, respectively. Urinary continence scores highly correlated for PCI and EPIC (r = 0.94). No comparison was possible for I-PSS with EPIC and PCI due to differences in the domains addressed by these questionnaires.

CONCLUSIONS

We have introduced methods to convert scores among the EPIC, PCI and SHIM questionnaires. While these conversion methods may introduce minor imprecision, to our knowledge they represent the best available tools to combine and compare patient reported outcomes that are assessed using different instruments in men undergoing radical prostatectomy or active surveillance.

Patient-reported urinary incontinence and erectile dysfunction following radical prostatectomy: results from the European Prostate Centre Innsbruck

INTRODUCTION

Urinary and erectile functions were assessed by using self-administered validated questionnaires in patients undergoing radical prostatectomy.

MATERIALS AND METHODS

In a prospective observational study, a total of 253 consecutive patients diagnosed with clinically localised prostate cancer between 2008 and 2009 at the European Prostate Centre Innsbruck were included. Patient-reported outcomes were assessed before radical prostatectomy and 12 months postoperatively using the validated International Consultation on Incontinence Questionnaire (ICIQ) and the International Index of Erectile Function (IIEF). The Wilcoxon signed-rank test and Chi square statistics were used for analysis.

RESULTS

The study showed that before radical prostatectomy, urinary incontinence of various severity grades was reported in 18.8, postoperatively in 63.0% (p < 0.001) and erectile dysfunction of various degrees was reported in 39.6 at baseline compared to 80.1% 12 months postoperatively (p < 0.001).

CONCLUSIONS

This study suggests that radical prostatectomy is associated with a significantly increased risk of urinary incontinence and erectile dysfunction 12 months postoperatively.

Validation of Portuguese version of Quality of Erection Questionnaire (QEQ) and comparison to International Index of Erectile Function (IIEF) and RAND 36-Item Health Survey

PURPOSE

To validate the Quality of Erection Questionnaire (QEQ) considering Brazilian social-cultural aspects.

MATERIALS AND METHODS

To determine equivalence between the Portuguese and the English QEQ versions, the Portuguese version was back-translated by two professors who are native English speakers. After language equivalence had been determined, urologists considered the QEQ Portuguese version suitable. Men with self-reported erectile dysfunction (ED) and infertile men who had a stable sexual relationship for at least 6 months were invited to answer the QEQ, the International Index of Erectile Function (IIEF) and the RAND 36-Item Health Survey (RAND-36). The questionnaires were presented together and answered without help in a private room. Internal consistency (Cronbach's α), test-retest reliability (Spearman), convergent validity (Spearman correlation) coefficients and known-groups validity (the ability of the QEQ Portuguese version to differentiate erectile dysfunction severity groups) were assessed.

RESULTS

We recruited 197 men (167 ED patients and 30 non-ED patients), mean age of 53.3 and median of 55.5 years (23-82 years). The Portuguese version of the QEQ had high internal consistency (Cronbach α=0.93), high stability between test and retest (ICC 0.83, with IC 95%: 0.76-0.88, p<0.001) and Spearman correlation coefficient r=0.82 (p<0.001), which demonstrated the high correlation between the QEQ and IIEF results. The correlations between the QEQ and RAND-36 were significantly low in ED (r=0.20, p=0.01) and non-ED patients (r=0.37, p=0.04).

CONCLUSION

The QEQ Portuguese version presented good psychometric properties and high convergent validity in relation to IIEF. The low correlations between the QEQ and the RAND-36, as well as between the IIEF and the RAND-36 indicated IIEF and QEQ specificity, which may have resulted from the patients' psychological adaptations that minimized the impact of ED on Quality of Life (QoL) and reestablished the well-being feeling.

Potency preservation following stereotactic body radiation therapy for prostate cancer

BACKGROUND

Erectile dysfunction after prostate radiation therapy remains an ongoing challenge and critical quality of life issue. Given the higher dose of radiation per fraction using stereotactic body radiation therapy (SBRT) there is concern that post-SBRT impotency would be higher than conventional radiation therapy approaches. This study sought to evaluate potency preservation and sexual function following SBRT for prostate cancer.

METHODS

Between February 2008 and March 2011, 216 men with clinically localized prostate cancer were treated definitively with SBRT monotherapy at Georgetown University Hospital. Potency was defined as the ability to have an erection firm enough for intercourse with or without sexual aids while sexual activity was defined as the ability to have an erection firm enough for masturbation and foreplay. Patients who received androgen deprivation therapy (ADT) were excluded from this study. Ninety-seven hormone-naïve men were identified as being potent at the initiation of therapy and were included in this review. All patients were treated to 35-36.25 Gy in 5 fractions delivered with the CyberKnife Radiosurgical System (Accuray). Prostate specific antigen (PSA) and total testosterone levels were obtained pre-treatment, every 3 months for the first year and every 6 months for the subsequent year. Sexual function was assessed with the Sexual Health Inventory for Men (SHIM), the Expanded Prostate Index Composite (EPIC)-26 and Utilization of Sexual Medication/Device questionnaires at baseline and all follow-up visits.

RESULTS

Ninety-seven men (43 low-, 50 intermediate- and 4 high-risk) at a median age of 68 years (range, 48-82 years) received SBRT. The median pre-treatment PSA was 5.9 ng/ml and the minimum follow-up was 24 months. The median pre-treatment total serum testosterone level was 11.4 nmol/L (range, 4.4-27.9 nmol/L). The median baseline SHIM was 22 and 36% of patients utilized sexual aids prior to treatment. Although potency rates declined following treatment: 100% (baseline); 68% (6 months); 62% (12 months); 57% (18 months) and 54.4% (24 months), 78% of previously potent patients had erections sufficient for sexual activity at 24 months post-treatment. Overall sexual aid utilization increased from 36% at baseline to 49% at 24 months. Average EPIC sexual scores showed a slow decline over the first two years following treatment: 77.6 (baseline); 68.7 (6 months); 63.2 (12 months); 61.9 (18 months); 59.3 (24 months). All sexual functions including orgasm declined with time. Prior to treatment, 13.4% of men felt their sexual function was a moderate to big problem which increased to 26.7% two years post treatment. Post-treatment testosterone levels gradually decreased with a median value at two year follow-up of 10.7 nmol/L. However, the average EPIC hormonal scores did not illustrate a statistically significant difference two years post-treatment. Review of the radiation doses to the penile bulb in this study, a potential marker of post-treatment sexual function, revealed that the dose was relatively low and at these low doses the percentage of the penile bulb receiving 29.5 Gy did not correlate with the development of ED.

CONCLUSIONS

Men undergoing SBRT monotherapy for prostate cancer report sexual outcomes comparable to those reported for conventional radiation modalities within the first 24 months after treatment. Longer follow-up is required to confirm the durability of these findings.

Nightly vs on-demand sildenafil for penile rehabilitation after minimally invasive nerve-sparing radical prostatectomy: results of a randomized double-blind trial with placebo

OBJECTIVES

To clarify the role of phosphodiesterase type 5 (PDE5) inhibitors in post-prostatectomy penile rehabilitation (PPPR). To compare nightly and on-demand use of PDE5 inhibitors after nerve-sparing minimally invasive radical prostatectomy (RP).

PATIENTS AND METHODS

We conducted a single-institution, double-blind, randomized controlled trial of nightly vs on-demand 50-mg sildenafil citrate after nerve-sparing minimally invasive RP. A total of 100 preoperatively potent men, aged <65 years, with scores on the Erectile Function domain of the International Index of Erectile Function (IIEF-EF) ≥26, underwent nerve-sparing surgery. The patients were randomized to either nightly sildenafil and on-demand placebo (nightly sildenafil group), or on-demand sildenafil and nightly placebo (on-demand sildenafil group; maximum on-demand dose six tablets/month) for 12 months. Patients then underwent a 1-month washout period. Validated measures of erectile function (IIEF-EF score and the Expanded Prostate Cancer Index Composite [EPIC]) were compared between treatment groups over the entire 13-month time course, using multivariable mixed linear regression models.

RESULTS

The treatment groups were well matched preoperatively (mean age 54.3 vs 54.6 years, baseline IIEF-EF score 29.4 vs 29.3, for the nightly vs the on-demand sildenafil groups, respectively). No significant differences were found in erectile function between treatments (nightly vs on-demand sildenafil) at any single timepoint after RP, after adjusting for potential confounding factors. When evaluated over all timepoints simultaneously, no significant effects of treatment group (nightly vs on-demand sildenafil) were found on recovery of potency, as assessed by absolute IIEF-EF scores (P = 0.765), on percentage of men returning to an IIEF-EF score >21 (P = 0.830), or on IIEF-EF score recovery to a percentage of baseline value (P = 0.778). When evaluated over all timepoints simultaneously, no significant effects of treatment group were found on secondary endpoints such as assessment of potency (including EPIC item 59 response 'erections firm enough for intercourse'), attempted intercourse frequency or confidence.

CONCLUSIONS

Erectile recovery up to 1 year after RP does not differ between previously potent men who use sildenafil nightly compared to on-demand. This trial does not support chronic nightly sildenafil as being any better than on-demand sildenafil for use in penile rehabilitation after nerve-sparing minimally invasive RP.

Stereotactic body radiation therapy (SBRT) for clinically localized prostate cancer: the Georgetown University experience

Background

Stereotactic body radiation therapy (SBRT) delivers fewer high-dose fractions of radiation which may be radiobiologically favorable to conventional low-dose fractions commonly used for prostate cancer radiotherapy. We report our early experience using SBRT for localized prostate cancer.

Methods

Patients treated with SBRT from June 2008 to May 2010 at Georgetown University Hospital for localized prostate carcinoma, with or without the use of androgen deprivation therapy (ADT), were included in this retrospective review of data that was prospectively collected in an institutional database. Treatment was delivered using the CyberKnife® with doses of 35 Gy or 36.25 Gy in 5 fractions. Biochemical control was assessed using the Phoenix definition. Toxicities were recorded and scored using the CTCAE v.3. Quality of life was assessed before and after treatment using the Short Form-12 Health Survey (SF-12), the American Urological Association Symptom Score (AUA) and Sexual Health Inventory for Men (SHIM) questionnaires. Late urinary symptom flare was defined as an AUA score ≥ 15 with an increase of ≥ 5 points above baseline six months after the completion of SBRT.

Results

One hundred patients (37 low-, 55 intermediate- and 8 high-risk according to the D’Amico classification) at a median age of 69 years (range, 48–90 years) received SBRT, with 11 patients receiving ADT. The median pre-treatment prostate-specific antigen (PSA) was 6.2 ng/ml (range, 1.9-31.6 ng/ml) and the median follow-up was 2.3 years (range, 1.4-3.5 years). At 2 years, median PSA decreased to 0.49 ng/ml (range, 0.1-1.9 ng/ml). Benign PSA bounce occurred in 31% of patients. There was one biochemical failure in a high-risk patient, yielding a two-year actuarial biochemical relapse free survival of 99%. The 2-year actuarial incidence rates of GI and GU toxicity ≥ grade 2 were 1% and 31%, respectively. A median baseline AUA symptom score of 8 significantly increased to 11 at 1 month (p = 0.001), however returned to baseline at 3 months (p = 0.60). Twenty one percent of patients experienced a late transient urinary symptom flare in the first two years following treatment. Of patients who were sexually potent prior to treatment, 79% maintained potency at 2 years post-treatment.

Conclusions

SBRT for clinically localized prostate cancer was well tolerated, with an early biochemical response similar to other radiation therapy treatments. Benign PSA bounces were common. Late GI and GU toxicity rates were comparable to conventionally fractionated radiation therapy and brachytherapy. Late urinary symptom flares were observed but the majority resolved with conservative management. A high percentage of men who were potent prior to treatment remained potent two years following treatment.

Standard operating procedure for the preservation of erectile function outcomes after radical prostatectomy

INTRODUCTION

Prostate cancer is common, and, thus, more men are being treated surgically. Long-term functional outcomes are of significant importance to the patient and their partners. Erectile function (EF) preservation (rehabilitation) has gained significant traction worldwide, despite the absence of definitive evidence supporting its use.

AIM

To review the effectiveness of specific pharmacological therapies and other erectogenic aids in the treatment of post-radical prostatectomy (RP) erectile dysfunction.

METHODS

A systematic literature review of original peer-reviewed manuscripts and clinical trials reported in Medline.

MAIN OUTCOME MEASURE

This review focused on the evaluation of interventions that aimed to improve EF recovery following RP.

RESULTS

Although well documented in animal models, studies supporting the rehabilitation with phosphodiesterase type 5 inhibitors in humans are scarce. Daily sildenafil has been used in trials (only one randomized placebo-controlled trial) with a significant improvement in erection recovery when compared to placebo or no rehabilitation but with a low return to baseline rates (27% vs. 4% placebo). Nightly vardenafil vs. on demand vs. placebo has been studied in the Recovery of Erections: INtervention with Vardenafil Early Nightly Therapy trial with no difference in erection recovery following RP. Intracavernosal injections, although widely used and attractive from a rehabilitation standpoint, does not yet have definitive supporting its role in rehabilitation. Vacuum erection devices use following RP has been reported, but there are no data to support its role as monotherapy. Intraurethral alprostadil was also studied vs. sildenafil in a multicenter, randomized, open-label trial, and no superiority was found.

CONCLUSIONS

At this time, we are unable to define what represents the optimal rehabilitation program in regard to strategies utilized, timing of intervention, or duration of treatment.

Prediction of erectile function following treatment for prostate cancer

CONTEXT

Sexual function is the health-related quality of life (HRQOL) domain most commonly impaired after prostate cancer treatment; however, validated tools to enable personalized prediction of erectile dysfunction after prostate cancer treatment are lacking.

OBJECTIVE

To predict long-term erectile function following prostate cancer treatment based on individual patient and treatment characteristics.

DESIGN

Pretreatment patient characteristics, sexual HRQOL, and treatment details measured in a longitudinal academic multicenter cohort (Prostate Cancer Outcomes and Satisfaction With Treatment Quality Assessment; enrolled from 2003 through 2006), were used to develop models predicting erectile function 2 years after treatment. A community-based cohort (community-based Cancer of the Prostate Strategic Urologic Research Endeavor [CaPSURE]; enrolled 1995 through 2007) externally validated model performance. Patients in US academic and community-based practices whose HRQOL was measured pretreatment (N = 1201) underwent follow-up after prostatectomy, external radiotherapy, or brachytherapy for prostate cancer. Sexual outcomes among men completing 2 years' follow-up (n = 1027) were used to develop models predicting erectile function that were externally validated among 1913 patients in a community-based cohort.

MAIN OUTCOME MEASURES

Patient-reported functional erections suitable for intercourse 2 years following prostate cancer treatment.

RESULTS

Two years after prostate cancer treatment, 368 (37% [95% CI, 34%-40%]) of all patients and 335 (48% [95% CI, 45%-52%]) of those with functional erections prior to treatment reported functional erections; 531 (53% [95% CI, 50%-56%]) of patients without penile prostheses reported use of medications or other devices for erectile dysfunction. Pretreatment sexual HRQOL score, age, serum prostate-specific antigen level, race/ethnicity, body mass index, and intended treatment details were associated with functional erections 2 years after treatment. Multivariable logistic regression models predicting erectile function estimated 2-year function probabilities from as low as 10% or less to as high as 70% or greater depending on the individual's pretreatment patient characteristics and treatment details. The models performed well in predicting erections in external validation among CaPSURE cohort patients (areas under the receiver operating characteristic curve, 0.77 [95% CI, 0.74-0.80] for prostatectomy; 0.87 [95% CI, 0.80-0.94] for external radiotherapy; and 0.90 [95% CI, 0.85-0.95] for brachytherapy).

CONCLUSION

Stratification by pretreatment patient characteristics and treatment details enables prediction of erectile function 2 years after prostatectomy, external radiotherapy, or brachytherapy for prostate cancer.

High-dose-rate brachytherapy as a monotherapy for favorable-risk prostate cancer: a Phase II trial

PURPOSE

There are multiple treatment options for favorable-risk prostate cancer. High-dose-rate (HDR) brachytherapy as a monotherapy is appealing, but its use is still investigational. A Phase II trial was undertaken to explore the value of such treatment in low-to-intermediate risk prostate cancer.

METHODS AND MATERIALS

This was a single-institution, prospective study. Eligible patients had low-risk prostate cancer features but also Gleason scores of 7 (51% of patients) and stage T2b to T2c cancer. Treatment with HDR brachytherapy with a single implant was administered over 2 days. One of four fractionation schedules was used in a dose escalation study design: 3 fractions of 10, 10.5, 11, or 11.5 Gy. Patients were assessed with the Common Terminology Criteria for Adverse Events version 2.0 for urinary toxicity, the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer scoring schema for rectal toxicity, and the Expanded Prostate Cancer Index Composite (EPIC) questionnaire to measure patient-reported health-related quality of life. Biochemical failure was defined as a prostate-specific antigen (PSA) nadir plus 2 ng/ml.

RESULTS

Between 2003 and 2008, 79 patients were enrolled. With a median follow-up of 39.5 months, biochemical relapse occurred in 7 patients. Three- and 5-year actuarial biochemical control rates were 88.4% (95% confidence interval [CI], 78.0-96.2%) and 85.1% (95% CI, 72.5-94.5%), respectively. Acute grade 3 urinary toxicity was seen in only 1 patient. There was no instance of acute grade 3 rectal toxicity. Rates of late grade 3 rectal toxicity, dysuria, hematuria, urinary retention, and urinary incontinence were 0%, 10.3%, 1.3%, 9.0%, and 0%, respectively. No grade 4 or greater toxicity was recorded. Among the four (urinary, bowel, sexual, and hormonal) domains assessed with the EPIC questionnaire, only the sexual domain did not recover with time.

CONCLUSIONS

HDR brachytherapy as a monotherapy for favorable-risk prostate cancer, administered using a single implant over 2 days, is feasible and has acceptable acute and late toxicities. Further follow-up is still required to better evaluate the efficacy of such treatment.

Sexual quality of life for localized prostate cancer: a cross-cultural study between Japanese and American men

Introduction

Race and ethnicity are important factors in health-related quality of life (QOL) because of racial differences in preferences for, and trust in, health systems. Such factors are likely to affect QOL and patient satisfaction with care.

Results

Using a self-reported questionnaire, Japanese men with prostate cancer reported lower sexual function scores at baseline. In detail, Japanese men were more likely than American men to report poor sexual desire, poor erection ability, poor overall ability to function sexually, poor ability to attain orgasm, poor quality of erections, infrequency of erections, infrequency of morning erections, and intercourse in the previous 4 weeks. However, Japanese men were less likely than American men to be concerned about their sexual function. Two years after surgery, American patients were more likely than Japanese patients to regain their baseline sexual function. The use of phosphodiesterase-5 (PDE-5) inhibitors has been widely publicized as the solution to erectile dysfunction after prostate cancer treatment. Although PDE-5 inhibitors have been available in Japan since 1999, it is striking that Japanese men with localized prostate cancer are much less likely (only 10%) to use PDE-5 inhibitors than American men.

Conclusion

Japanese patients with localized prostate cancer report worse sexual function but are less concerned about their reduced function. In the absence of a biological explanation for such differences, however, we suspect that cultural differences may explain the differences between QOL survey results from Japanese or American men with prostate cancer.