A prospective analysis of the effects of nerve-sparing radical prostatectomy on urinary continence based on expanded prostate cancer index composite and international index of erectile function scoring systems

Abstract

Purpose: This study aims to objectively characterize the effect of successful nerve sparing (NS) during radical prostatectomy (RP) on postoperative urinary continence (UC) using International Index of Erectile Function (IIEF)-scores and a previously described Expanded Prostate Cancer Index Composite (EPIC) score cutoff value (COV) for UC. Several notable studies on this topic present conflicting outcomes. This is largely due to a lack of clear definitions and consensus regarding preserved erectile function (EF) and UC. Methods: This study is comprised of all patients who underwent RP at the Kantonsspital Baden, Switzerland, between 2004 and 2013. Patients completed self-assessment questionnaires for UC (EPIC) and EF (IIEF) pre- and postoperatively (3, 6, 9, 12, 18, and 24 months; yearly thereafter). We used a previously described EPIC subscore COV, with "satisfactory continence" signified by a score > 85. Statistical analysis was performed using Kaplan-Meier and Cox regression analyses for "surgeon-" and "IIEF-defined" NS definitions. Results: Of 236 men with a median age of 63 years (interquartile range [IQR], 59-66 years) and median follow-up time of 48 months (IQR, 30-78 months), 176 underwent unilateral (n=33) or bilateral (n=143) NS RP. Fifty-four underwent non-NS (NNS) RP. Kaplan-Meier analyses identified the following risk factors for UC: age, prostate volume, cancer risk group, and NS status. In surgeon-defined NS RP cases, multivariate analysis for regaining continence demonstrated no significant difference (hazard ratio [HR], 0.78; 95% confidence interval [CI], 0.48-1.25; P=0.3). With successful IIEF-defined NS RPs, regression analysis demonstrated no significant difference (HR, 0.89; 95% CI, 0.59-1.35; P=0.58). Conclusions: In our population, analysis and comparison of surgeon- and IIEF-defined NS and NNS cohorts revealed that NS RP did not improve postoperative UC. The conservation of UC alone should not motivate surgeons or patients to pursue NS RP.