Racial Variation in Membranous Urethral Length and Postprostatectomy Urinary Function

Urinary incontinence remains a significant postprostatectomy sequala. While it has been found that many patient and technical factors contribute to postprostatectomy incontinence, the impact of anatomical differences by races has not been studied. Shorter preoperative membranous urethral length (MUL) on prostate magnetic resonance imaging has been associated with a higher risk of postprostatectomy incontinence. We compared MUL between Asian and non-Asian men and their postprostatectomy urinary function using the Expanded Prostate Cancer Index Composite for Clinical Practice (EPIC-CP). We found that MUL was significantly shorter for Asian (7.9 mm, 95% confidence interval [CI] 7.5–8.3) than for non-Asian men (10.9 mm, 95% CI 10.2–11.7), with a mean difference of 3.0 mm (95% CI 2.15–3.87; p < 0.01). In addition, Asian men had significantly worse EPIC-CP urinary scores ≥12 mo after prostatectomy (3.82, 95% CI 2.47–5.17) in comparison to non-Asian men (1.95, 95% CI 1.11–2.79), with a mean difference of 1.87 (95% CI 0.32–3.42; p = 0.022). Confirmatory studies are needed to explore racial differences in MUL and its effect on postprostatectomy incontinence. PATIENT SUMMARY: We compared the length of a specific section of the urethra (called the membranous urethra) and urinary function after removal of the prostate between Asian and non-Asian men. We found that the membranous urethra is significantly shorter in Asian men and they have worse urinary continence after removal of the prostate. More studies are needed to confirm our findings.