AbstractObjectivesTo evaluate longitudinal changes in lower urinary tract symptoms (LUTS) after artificial urinary sphincter (AUS) implantation in patients undergoing radiation therapy (RT) in comparison to those in non‐irradiated patients.MethodsThis retrospective study included 20 and 51 patients with and without a history of pelvic RT (RT and non‐RT group, respectively) who were treated with primary AUS implantation for post‐radical prostatectomy incontinence between 2010 and 2020. Longitudinal changes in the International Consultation on Incontinence Questionnaire‐Short Form (ICIQ‐SF), the International Prostate Symptom Score (IPSS), and the Overactive Bladder Symptom Score (OABSS) were calculated with a linear mixed model.ResultsIn the RT and non‐RT group, 18 (90%) and 48 (94%) patients achieved social continence, defined as daily pad use ≤1 at 1 month after activation of AUS, respectively (p = .555). During the mean follow‐up of 38 months, ICIQ‐SF, IPSS, and OABSS significantly improved after AUS implantation in both the RT and non‐RT groups. In the RT group, ICIQ‐SF, IPSS, and OABSS subsequently deteriorated with a slope of 0.62/year (p = .010), 0.55/year (p = .025), and 0.30/year (p = .007), respectively. In the non‐RT group, no significant longitudinal changes in subsequent IPSS and OABSS were observed, although ICIQ‐SF significantly deteriorated (0.43/year, p = .006). Comparing between the groups, the slopes of IPSS and OABSS were significantly greater in the RT group than in the non‐RT group (p < .001, and .015, respectively).ConclusionsLongitudinal deterioration in LUTS that improved immediately after AUS implantation was observed in patients with a history of pelvic RT, but not in patients without a history of pelvic RT.