ABSTRACT: INTRODUCTION:Despite the importance of using penile injections as part of a penile rehabilitation program, men have difficulty complying with these programs. AIM:To test a novel psychological intervention based on Acceptance and Commitment Therapy for erectile dysfunction (ACT-ED) to help men utilize penile injections. METHODS:This pilot randomized controlled trial (RCT) recruited men who were beginning a standard care (SC) structured penile rehabilitation program following radical prostatectomy. The SC program instructed patients to use penile injections 2 to 3 times per week. Participants were randomized to SC+ACT-ED or SC+enhanced monitoring (EM). Over 4 months, patients in the SC+ACT-ED group received SC plus 4 ACT sessions and 3 ACT phone calls; those in the EM group received SC plus 7 phone calls from an experienced sexual medicine nurse practitioner. Participants were assessed at study entry and at 4 and 8 months. For this pilot study, the goal was to determine initial efficacy (ie, effect sizes, where d = 0.2 is small, d = 0.5 is medium, and d = 0.8 is large). MAIN OUTCOME MEASURE:Primary outcomes were feasibility and use of penile injections. Secondary outcomes were ED treatment satisfaction (ie, Erectile Dysfunction Inventory of Treatment Satisfaction, or EDITS), sexual Self-Esteem and Relationship (SEAR) quality, sexual bother (SB), and prostate cancer treatment regret. RESULTS:The 53 participants were randomized (ACT, n = 26; EM, n = 27). The study acceptance rate was 61%. At 4 months, the ACT-ED group utilized more penile injections per week (1.7) compared to the EM group (0.9) (d = 1.25; P = .001) and was more adherent to penile rehabilitation compared to the EM group (ACT, 44%; EM, 10%; relative risk [RR], 4.4; P = .02). These gains were maintained at 8 months for injections per week (ACT, 1.2; EM, 0.7; d = 1.08; P = .03) and approached significance for adherence (ACT, 18%; EM, 0%; P = .10). At 4 months, ACT-ED, compared to EM, reported moderate effects for greater satisfaction with ED treatment (d = 0.41; P = .22), greater sexual self-esteem (d = 0.54; P = .07) and sexual confidence (d = 0.48; P = .07), lower sexual bother (d = 0.43; P = .17), and lower prostate cancer treatment regret (d = 0.74; P = .02). At 8 months, moderate effects in favor of ACT-ED were maintained for greater sexual self-esteem (d = 0.40; P = .19) and less treatment regret (d = 0.47; P = .16). CLINICAL IMPLICATIONS:ACT concepts may help men utilize penile injections and cope with the effects of ED. STRENGTHS AND LIMITATIONS:Strengths include use of an innovative intervention utilizing ACT concepts and pilot RCT. Limitations include the pilot nature of the study (eg, small samples size, lack of statistical power). CONCLUSION:ACT-ED is feasible and significantly increases the use of penile injections. ACT-ED also shows promise (moderate effects) for increasing satisfaction with penile injections and sexual self-esteem while decreasing sexual bother and prostate cancer treatment regret. Nelson CJ, Saracino RM, Napolitano S, et al. Acceptance and Commitment Therapy to Increase Adherence to Penile Injection Therapy-Based Rehabilitation After Radical Prostatectomy: Pilot Randomized Controlled Trial. J Sex Med 2019; 19:1398-1408.