Recovery of urinary continence following radical prostatectomy: the impact of prostate volume--analysis of data from the CaPSURE Database.

PURPOSE: Improved urinary function following radical prostatectomy due to bladder outlet obstruction from subclinical benign prostatic hyperplasia has been described. We determined if prostate volume determined by preoperative transrectal ultrasound could predict recovery of urinary function and continence following radical prostatectomy.
MATERIALS AND METHODS: We identified all 4,984 patients who underwent radical prostatectomy in the CaPSURE national disease registry of men with prostate cancer. Only the 2,097 men who had data available on preoperative prostate volume by transrectal ultrasound, and complete preoperative and postoperative data available on urinary function using the UCLA-PCI were selected for study. Transrectal ultrasound volume was categorized as less than 25, 25 to 50 cc or greater than 50 cc. Univariate and mixed multivariate analyses were performed to determine the association between transrectal ultrasound based prostate volume and continence, as measured by urinary function scores 6 months to 2 years following radical prostatectomy. Analyses were controlled for baseline urinary function as well as other variables, such as body mass index, time of urinary function assessment and patient age at diagnosis. Total and individual item scores on the urinary function subscale were used as outcome variables in separate models.
RESULTS: Median transrectal ultrasound prostate volume was 35 cc (IQR 27-47.8). In the ANOVA for mixed models patient age, time of urinary function assessment, body mass index and transrectal ultrasound prostate volume were independent predictors of urinary continence. Patients with prostate volume greater than 50 cc had lower rates of continence, as assessed by urinary function scores 6 months and 1 year after radical prostatectomy, but scores equalized across all volume ranges by 2 years after radical prostatectomy. The individual domains most significantly affected were urinary control (p = 0.02), urine leakage during sexual activity (p = 0.0016) and urine leakage frequency (p = 0.0175).
CONCLUSIONS: These data indicate that baseline prostate volume is a predictor of recovery of urinary function after radical prostatectomy. Men with larger volume prostates have lower levels of continence up to 2 years after radical prostatectomy. A potential reason could be subclinical bladder dysfunction related to benign prostatic hyperplasia that manifests after surgery.