Predictors of Patient-Reported Incontinence at Adjuvant/Salvage Radiotherapy after Prostatectomy: Impact of Time between Surgery and Radiotherapy

SIMPLE SUMMARY: The levels of urinary incontinence (UI) at adjuvant/salvage radiotherapy (ART/SRT) start strongly influence long-term UI recovery, possibly inducing clinicians to postpone radiotherapy “as much as possible” in order to maximize UI recovery, but possibly reducing radiotherapy efficacy. Our study analyzed UI recovery from prostatectomy to ART/SRT by means of the International Consultation on Incontinence Questionnaire-Short Form filled-in by patients at ART/SRT start. Three endpoints were investigated: frequency and amount of urine loss and the “subjective” patient-perceived detrimental impact on quality of life, as well as the possible influence of clinical and personality variables. The time elapsed from prostatectomy to radiotherapy start was the strongest predictor for each UI endpoint, all improving between four and eight months after prostatectomy, but without any additional long-term recovery. ABSTRACT: Background: Baseline urinary incontinence (UI) strongly modulates UI recovery after adjuvant/salvage radiotherapy (ART/SRT), inducing clinicians to postpone it “as much as possible”, maximizing UI recovery but possibly reducing efficacy. This series aims to analyze the trend of UI recovery and its predictors at radiotherapy start. Methods: A population of 408 patients treated with ART/SRT enrolled in a cohort study (ClinicalTrials.gov #NCT02803086) aimed at developing predictive models of radiation-induced toxicities. Self-reported UI and personality traits, evaluated by means of the International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-SF) and Eysenck Personality Questionnaire - Revised (EPQ-R) questionnaires, were assessed at ART/SRT start. Several endpoints based on baseline ICIQ-SF were investigated: frequency and amount of urine loss (ICIQ3 and ICIQ4, respectively), “objective” UI (ICIQ3 + 4), “subjective” UI (ICIQ5), and “TOTAL” UI (ICIQ3 +4 + 5). The relationship between each endpoint and time from prostatectomy to radiotherapy (TTRT) was investigated. The association between clinical and personality variables and each endpoint was tested by uni- and multivariable logistic regression. Results: TTRT was the strongest predictor for all endpoints (p-values ≤ 0.001); all scores improved between 4 and 8 months after prostatectomy, without any additional long-term recovery. Neuroticism independently predicted subjective UI, TOTAL UI, and daily frequency. Conclusions: Early UI recovery mostly depends on TTRT with no further improvement after 8 months from prostatectomy. Higher levels of neuroticism may overestimate UI.