A Cohort Study Comparing the Novel 'Sexual Minorities and Prostate Cancer Scale' to the Gold Standard Questionnaires Investigating Erectile Dysfunction and Incontinence Following Robotic Assisted Radical Prostatectomy

Prostate cancer treatments negatively impact sexual and urinary function. Prostate cancer is increasing in incidence and through rapid uptake of the screening tool, PSA, many patients are getting diagnosed younger and with lower risk disease. With this shift, cancer survivorship both in its assessment and management, is becoming a growing issue as more patients live with the after effect of prostate cancer treatments. Many tools have been developed to assess sexual and urinary function following treatments such as the Expanded Prostate Cancer Index (EPIC), ICIQLUTSqol or the International Index of Erectile Function (IIEF). However, these do not capture the experience of gay, bisexual and transsexual (sexual minority) patients.

In previous studies of heterosexual prostate cancer patients, erectile dysfunction was reported in 51-60% after 24 months post-treatment and urinary incontinence 7-14% at 24 months. Whilst there is common ground in the obstacle for sexual recovery following surgery, sexual minority patients face additional challenges including erections that are too weak for anal insertive sex [], loss of ejaculate (which is a central to many sexual minority men) [], arousal incontinence and climacturia during oral sex [] or the potential loss of sexual pleasure in receptive anal sex []. In a recent study of 193 sexual minority prostate cancer patients, only 12% described their overall sexual functioning as 'very good' or 'excellent'.

In a review of twelve common sexual functioning scales in prostate cancer survivors [], all focused primarily or exclusively on erectile function and seven explicitly defined intercourse as vaginal penetration. Thus, existing measures used in clinical research and practice may lack validity in measuring quality of life among sexual minority patients. This not only fails to consider these aspects in the sexual minority survival of cancer but also under reports the scale of the problem in the literature.

Radical prostatectomy is a main treatment for low-intermediate risk prostate cancer and at Guy's and St Thomas's, surgeons undertake around 300/year. The investigators follow these patients up with IIEF at 3, 6, 12 and 24 months following their surgery as standard.

The Restore Group, has developed the Sexual Minorities and Prostate Cancer Scale (SMACS). This study used 401 sexual minority patients whom completed an online battery of urinary and sexual functioning including a new 37-item instrument about their sexual functioning post treatment for prostate cancer. Confirmatory factor analysis was used to determine the construct validity with three subscales revealed: sexual distress, urinary incontinence in sex and problematic receptive anal sex. Cronbach's alphas ranged 0.86-0.93. For criterion validity, sexual distress correlated strongly with EPIC sexual function and bother scores. Urinary incontinence in sex correlated weakly with EPIC sexual function and bother (r=0.10-0.19). Problematic receptive anal sex was weakly correlated with each EPIC scale (r=0.12-0.29).