Concurrent extension of bladder cancer to the intramural ureter and prostatic urethra increases the risk of urethral cancer in patients undergoing radical cystectomy.

PURPOSE: Bladder cancer extension to the prostatic urethra is a well-known risk factor for urethral recurrence. This study investigated whether concurrent involvement of the intramural ureter, in addition to the prostatic urethra, further increases the urethral cancer risk. METHODS: We retrospectively analyzed 316 male patients who underwent radical cystectomy for bladder cancer between 2002 and 2020. We assessed the prevalence of tumor extension to the prostatic urethra and intramural ureter and evaluated its association with synchronous and metachronous urethral cancer. Synchronous urethral cancer was defined as cancer detected in the pendulous, bulbar, or membranous urethra, whereas metachronous urethral cancer was defined as cancer developing in the remnant urethra. Logistic regression analyses were performed to identify risk factors for urethral cancer. RESULTS: The median follow-up duration was 61 months. Among the 316 patients, 148 underwent prophylactic urethrectomy during cystectomy, and 168 did not. Urethral cancer occurred in 12 (3.8%): 8 (5.4%) had synchronous urethral cancer, and 4 (2.4%) developed metachronous urethral cancer. In multivariate analysis, the odds ratios for urethral cancer were 3.91 (95% confidence interval [CI], 0.84-18.20; p = 0.082) for cancer extension limited to the prostatic urethra and 12.60 (95% CI 2.75-57.60; p = 0.001) for cancer extension to the prostatic urethra and intramural ureter, compared with no cancer extension to the prostatic urethra. CONCLUSION: Two distinct patterns of prostatic urethral involvement exist. Bladder cancer extending to the prostatic urethra and intramural ureter was associated with an increased risk of synchronous and metachronous urethral cancers.