Creation and Psychometric Validation of the Sexual Minorities and Prostate Cancer Scale (SMACS) in Sexual Minority Patients-The Restore-2 Study

Abstract

ABSTRACT Background Existing measures of sexual functioning in prostate cancer survivors focus primarily on erectile function and do not adequately measure the experiences of sexual minority men. Aim To develop and psychometrically evaluate a new scale to measure sexual functioning among sexual minority men with prostate cancer. Methods Sexual minority prostate cancer patients (n = 401) completed an online battery of urinary and sexual functioning tests in 2019, including a new 37-item instrument about their sexual functioning post-treatment for prostate cancer. Outcomes We used confirmatory factor analysis to determine the construct validity of a new scale including five subscales: a four-factor model for all participants (n = 401) evaluated Sexual Satisfaction, Sexual Confidence, Frequency of Sexual Problems, and Urinary Incontinence in Sex. A single-factor model completed only by participants who had attempted or desired receptive anal sex (n = 255) was evaluated in the fifth subscale: Problematic Receptive Anal Sex. To evaluate criterion validity, we calculated the intercorrelations between each Sexual Minorities and Prostate Cancer Scale (SMACS) subscale and four related scales: the Expanded Prostate Cancer Index Composite-50 (EPIC), the Functional Assessment of Cancer Therapy-Prostate, the Brief Symptom Inventory-18, and the International Consultation on incontinence questionnaire. Cronbach’s alphas were calculated to measure internal consistency (ie, reliability). Results Cronbach’s alpha values ranged from 0.64 to 0.89. Loadings (0.479–0.926) and model fit indices were strong (Root Mean Square Error of Approximation: 0.085, Standardized root mean squared residual: 0.063, comparative fit index: 0.927, Tucker-Lewis Index: 0.907). For criterion validity, Sexual Satisfaction, Sexual Confidence, and Frequency of Sexual Problems were moderately correlated with EPIC function and bother scores (r = 0.50–0.72) and Urinary incontinence in sex correlated moderately with EPIC Urinary Function and International Consultation on incontinence questionnaire scores (0.45–0.56). Clinical Implications The SMACS can be used by clinicians and researchers to comprehensively measure sexual functioning in sexual minority men, in conjunction with existing scales. Strengths and limitations This new scale is validated in a large, geographically diverse cohort of sexual minority cancer survivors and fills an important gap in existing measures of sexual functioning. Limitations include a lack of a validation sample. Conclusion The SMACS is a valid and reliable new scale that measures sexual minority men’s experience of urinary incontinence in sex, problematic receptive anal sex, and sexual distress.