MP80-15 HISTOLOGICAL MEASUREMENT OF THE MEMBRANOUS URETHRAL LENGTH IN RADICAL PROSTATECTOMY SPECIMEN PREDICTS POSTPROSTATECTOMY URINARY INCONTINENCE.

INTRODUCTION AND OBJECTIVES: Length of membranous urethra (MU) and the amount of striated muscle (SM) removed with the apical aspect of the prostate can be predictive of urinary incontinence after radial prostatectomy. The aim of the present study was to assess whether these histological measurements correlate with urinary incontinence after laparoscopic radical prostatectomy (LRP) and robotassisted radical prostatectomy (RARP). METHODS: We retrospectively reviewed the charts of 179 patients who underwent LRP (n1⁄498) and RARP (n1⁄481) from July 2010 to May 2014. Two uropathologists reviewed the hematoxylin and eosin sections of the apical margin to measure the length of MU (distance from the resection margin of the urethra to the prostate apex) and semiquantitatively assess the amount of SM, which was expressed as the percentage of total apical margin surface area occupied by SM. Patient-reported continence status was determined at 3, 6 and 24 months postoperatively, with urinary continence considered as 0 1 pads. The histological measurements were compared between continent and incontinent patients using Student’s t test. Multivariable logistic regression analyses were also performed to determine adjusted odds ratios (OR). RESULTS: Patients had a median age of 67 years at surgery. Urinary incontinence was observed in 55% of the patients after 3 months, 22% after 6 months and 10% after 24 months. The length of MU was significantly longer in patients with incontinence compared to those with continence at 3, 6 and 24 months, Fig. 1). While, no significant differences were observed in the amount of SM between the groups at any time point. Multivariable analyses revealed that the length of MU was associated with significantly increased odds of incontinence at 3 months (OR, 1.46; 95% CI, 1.09-2.00), 6 months (OR, 1.58; 95% CI, 1.14-2.23) and 24 months (OR, 2.43, 95%CI 1.44-4.49) after adjustment for age, length of membranous urethra measured on preoperative MRI, preservation of the neurovascular bundle and type of surgery. CONCLUSIONS: These results demonstrated that the length of MU in the pathology specimen was an independent predictor of urinary incontinence after radical prostatectomy. Care should be taken to preserve maximal length of MU for optimal continence outcomes.