The association between the parameters of uroflowmetry and lower urinary tract symptoms in prostate cancer patients after robot-assisted radical prostatectomy

OBJECTIVE: To investigate changes in uroflowmetry parameters in men undergoing robot-assisted radical prostatectomy (RARP) for prostate cancer. MATERIALS AND METHODS: Four hundred and twenty-eight patients received uroflowmetry testing before and after RARP from November 2011 to December 2018. Clinicopathological data, including age, initial prostate-specific antigen (PSA), prostate volume, clinical stage, body mass index (BMI), uroflowmetry parameters, and core lower urinary tract symptom scores (CLSS) were retrospectively obtained from clinical records. Changes in uroflowmetry parameters were analyzed for statistical predictors and effects on post-operative outcomes. RESULTS: A significant increase in maximum flow rate (MFR) and decreases in voided volume (VV) and post-void residual urine (PVR) were seen. In multivariate analysis, age was a negative predictor of MFR increase, while prostate volume was a positive predictor of PVR decrease and MFR increase. VV decrease led to worse incontinence symptoms, while PVR decrease and MFR increase led to improvement in voiding symptoms such as slow stream and straining. Continence recovery curves showed that VV decrease were associated with a delay in continence recovery. CONCLUSIONS: Significant changes were seen in uroflowmetry results after RARP, each parameter directly related to urinary symptoms. In particular, VV decrease was associated with a worsening of incontinence symptoms and continence recovery.